Surefire X400 / Streamlight TLR-2 Design Summary

Let me preface this with a few words. I am not HSLD, and I do not work for any firearm company or publication. I am not associated with any whatsoever. I am also not an engineer, but fairly electro-mechanically inclined. I am also not a writer.

This is completely un-biased review of two lights. I have used both the Streamlight TLR-2 and Surefire x400 for a while. Of the samples I have (6 TLR-1s, 3 TLR-2s, 1 TLR-3 and 2 X400s. None of them have ever quit on me for any reason. I tend to use them fairly hard and don’t pamper them at all.

I do have this problem… if I get intrigued enough to know how something operates, I will take it apart, no exceptions; I cannot go on without knowing.

This review will be conducted slightly different from most reviews; it is strictly a design / build quality review focused on those elements alone. There are some comments at the end about actual use, but I do not have enough hours on the lights in harsh environments to write an educated review. I’ll leave that to the professionals. Also absent from this review will be cosmetic notes. I don’t care about how crisp the laser engraving is or if the anodizing matches the finish on my gun.

I have taken both lights apart to their individual components, to the point of (probably) destroying my X400. I have literally had them both stripped down to the smallest component level possible with the tools available.

Build Quality / Design

Surefire X400

The Surefire X400 has a quality LED and Laser Diode. The circuit boards are also well designed and manufactured. Solder work has been high quality at all solder points. I tested several solder points by pulling the wires from different angles. In all cases, the wires broke before the solder points. Keep in mind this is a sample set of one.

The body of the X400 is machine from a single block of aluminum. There is no wasted space and the unit is designed as lean as possible without sacrificing structural integrity. The anodizing in even and the body is anodized inside an out; I did not see any possible weaknesses for corrosion.

When I unscrewed the Surefire head, it broke the connection points between the battery terminal PCB and what I will call the logic board. The logic board distributes power based on the selector switch position. This is then transferred back to the LED or the laser diode. The logic board also contains the laser diode driver. The logic board and the LED driver board are press fit into the head and shock mounted with some kind of epoxy. Tolerances are tight and the design is very good. I know how it's assembled now, and it makes a lot of sense from a reliability / durability standpoint. The glass lens is beefy and well mounted between the housing flange and reflector. The way surefire assembles this light makes it nearly impossible for an end user to remove the head, as there is no need to change the LED, this should be not be end user serviceable.

The laser module is mounted via two long screws and is nestled in a milled channel. There is a thick rubber gasket that seals both the body and the laser module from the elements. Thread engagement is adequate. Wires run from the logic board through a plastic conduit into the laser module. Three wires go to the switch and three to the laser diode. The switching mechanism is a work of art. The selector lever is mounted via a press fit cross pin to the selector and runs the full length of the selector switch giving the plastic selector some rigidity and durability, when you flip modes; it turns a rotary switch to one of five positions. The positive click is a result of two ball bearings interfacing with a molded plastic race. A strong spring pushes the bearings apart into recesses. That is the reason the click is so positive and will likely never wear out. The entire selector unit is screwed into the back of the aluminum laser housing via a threaded steel insert. Another important note here is that the actual selector PCB has a mating recess milled into the laser housing. So no matter how many times you switch the mode, the PCB will never fail and rotate with the switch. On a side note, the attention to detail like previously noted is apparent everywhere you look on the light. Little things like this make a big difference. It is also integrated with the molded plastic selector detent sleeve. Behind the selector module is a strong spring which pushes the laser module forward into the centering ball and socket up forward. There are two very strong springs which act counter to the windage and elevation adjustment screws. These springs are very strong and large in size for what they do. The spring seating cups are also deep enough to keep them well aligned and not fall out if you adjust the laser to full negative travel. The laser module is made out of brass (as most are) and has some nice features. The adjustment spring flats are large, and there is a centering ball machined into the front of the module. This mates with a socket milled into the laser module. The spring tension from behind keeps the ball securely centered in the socket. The windage and elevation adjustment screws are large diameter with a lot of thread engagement. They also have a light thread lock applied to keep them from moving. The size and thread engagement is a huge plus.

The laser diode is also seated very nicely. The diode is put in from the front, and then a long threaded insert (retention nut) is screwed in from the face to sandwich and concentrically center the diode in the housing. The collimator is then screwed in on top of the retention nut. The collimator has two O-rings to keep it from moving and seal it against the elements. This is also very important. Any movement in the collimator will change your nice tight dot into a long flat line. (You can screw the collimator in and out to focus the laser). Secured into the laser housing is a second lens to protect the collimator and keep dust / dirt, etc out.

The mounting system is also well thought out. The floating rail interface is dovetailed into the body and the locking system is of ample size and has deep thread engagement. You could never strip it. The negative limit stop is a stainless steel pin press fit into the floating rail interface. The battery door / switch system is also well designed. The door hinge is a stainless steel bar pressed into either side of the body. The important point to note here is that the door only engages the outermost part of the hinge, putting all of the pressure at the strongest points. The locking mechanism is designed the same way, with a stainless locking bar and a strong spring to latch it closed. The switch itself is deigned well and very stout. There is an O-ring with a lot of real estate to seal the door. The O-ring is tapered. On hinged doors, a tapered O-ring is preferred as it will provide a better seal should the pressure on either side of the battery door be different.

The activation switch is well designed and protected. Four small press fit pins secure the cover plate over the switch hinge, which is anchored on both sides. When you move the switch, a ramp on the inside of the switch presses in both sides of the actual switching unit. This is a redundant system and solid. This is also the method used when pressing the switch forward for momentary activation.

One important note on the battery contacts; they are very strong, and wound so as to not protrude far from the battery door. This means the battery can never out-accelerate them and lose contact during firing. They should also never wear out.

Build Quality / Design

Streamlight TLR-2

The body of the Streamlight TLR-2 is milled from a solid block of aluminum. However the laser module is housed in a molded plastic body. The Streamlight head screws onto the body but it not thread locked. There is a large O-ring to seal out the elements. There are no user-serviceable parts inside here. The LED Driver PCB is mounted to the body of the unit and not the head. One positive aspect of this is the lens housing can be changed easily should the lens break. The laser module is secured to the body via 4 small screws. Screw size is smaller, and thread engagement is acceptable. There is a good sized gasket that seals the unit from water / dust. Etc. The laser module holds the laser housing and selector switch. The switch is an off the shelf 3 position switch, the switch is held on by a nut that has a rubber gasket as well. The switch has an anti-rotation pin to keep it aligned. The pin is set into the plastic laser housing. This shouldn’t be a problem as there is no rotational force on the switch. The laser adjustment screws are very small and are threaded into brass inserts. These inserts are molded into the plastic laser module. There is a single small spring that provides pressure against the two adjustment screws at a 45 degree angle. The laser module itself is brass and secured forward by an interesting design. There is a hole in the front of the plastic laser module. The brass housing has a threaded portion that fits through that hole surrounded by a rubber gasket. A steel lock nut is then secured to the laser module. This pulls the laser module hard against the rubber gasket, sealing the front of the unit and providing a pivot point for laser adjustment. The diode is secured in the laser housing with strong epoxy. There is no exterior lens to provide protection from the collimator. The collimator is recessed; this is good to protect it against damage, but bad if you get mud in it, as it would be very difficult to clean.

The rail locking mechanism is strong, but has less thread interface than the X400. I doubt you will ever strip it though. Negative travel over stop is accomplished by a C-clip on the tension bolt. The battery door is strong and has well designed contact points for the battery. They are thick guage but wound longer than the X400. The battery door locking mechanism is a slot and tab design, where the door has a tab that fits into a slot and acts as a hinge, the locking mechanism is formed spring steel that acts as a locking tab to secure the O-ring tight. The O-ring is flat, but compresses well enough to seal the unit. The switching mechanism is well designed, though not as positive as the surefire. A single bolt holds the selector lever to the battery door housing. The screw is thread locked, but on this unit, rotates with the switch. This may loosen the threads over time and create a problem.

Comparative Summary

Overall, the surefire has a better design and build quality; this is reflected in the price. Machine work is excellent on both, but the X400 design lends itself to more time on the CNC machine. From my standpoint, surefire spent a lot of time designing the really important points that would be prone to failure under hard user. The battery door and hinge mechanism is well designed and should not wear over time. The battery door on the Surefire is semi-captive, the TLR is free floating. Everything on the Surefire has a very positive click, from the selector switch to the activation switch, and battery door latch. Surefire uses much larger laser adjustment screws with longer thread interface, Streamlight opted for smaller diameter screws into molded inserts. The laser centering design on the surefire also lends itself to long term zero retention and no problems caused by recoil. The windage and elevation springs is a night and day difference. Surefire uses two heavy gauge springs with deep seated cups. Streamlight uses one light gauge spring at a 45 degree angle. The switching mechanism is also much better on the surefire; they use proprietary PCB’s with roller bearing position locks. Streamlight uses an off the shelf 3 position switch. While this switch will probably provide years of service, it extends out the back of the unit, and may break or be damaged if something hits it. The laser diode is also secured more appropriately on the Surefire, by mechanical lock. The TLR-2 diode is secured by epoxy. This may not present a problem as the epoxy is strong. The Surefire collimator / lens design is more robust and better engineered. Having an external lens is a great design feature that should also be an operational requirement. If the lens gets muddy, a quick wipe will fix it, trying to clean the lens on the TLR would be much more difficult. I also believe Surefire spent more time on thermal engineering the light. There is more air-space and cooling surface for both the LED and Laser Diode Driver. The Streamlight is very compact. I haven’t had a chance to measure temps, so that may be untrue. But it certainly looks to be better designed. The X400 is designed with a smaller aperture bezel, but throws light just as well, this is a product of reflector design. A smaller diameter and stouter lens means less chance of breaking it.

Across the spectrum, Surefire chose larger and stouter components, from spring gauge, to the quality of the switching mechanism, materials, and machining time. These are complex units build to suit a specific need. And those that use them operationally cannot have them fail at the wrong time.

Here is a quick tally sheet formed from my opinion.

Overall Design – Surefire Wins
Build Quality – Surefire Wins
Thermal Engineering – Surefire Wins
Materials - Surefire Wins
Operational Considerations - Surefire Wins
Locking Mechanism - Surefire Wins
Battery Contacts - Surefire Wins
Switch Design - Surefire Wins
Selector Switch Design - Surefire Wins
Waterproofing - Surefire Wins
Price – Streamlight Wins

I always disliked Surefire because of the high price; I just always thought they asked too much when other products performed just as well. Granted I am not “in country” beating my light up day and in and day out. But if I were, I would definitely grab a Surefire anything over any other brand of light. I have completely taken apart several lights from several different manufacturers in the past, across the board Surefire builds higher quality kit. Now, keep in mind, I have several Streamlights and never a problem, so their design may be solid and well thought out. No doubt the engineers there spend some time building a quality product.

I actually prefer the TLR switchology over X400. I like that one side of the switch is momentary, and the other is constant on. And you can quickly turn constant on off without activating the other side. Surefire does make additional switch plates, so I may have to give one of those a shot in the near future. I have used a TLR-1s on a pistol and absolutely hated it. For the simple reason that during fire, my finger would double bump the switch and put it into strobe mode. Maybe that’s a good thing, and maybe it’s a training issue. It bothered me though.

I would like to test the Customer Service at both companies, but I doubt either would take back a box of parts.

Hopefully my experiment will benefit someone in choosing a light.

After this experiment, I will be changing all of my IR TLR-2 units to IR X400 units. I will also change the TLR units I am using on “Go to” guns to X300’s. I will most likely keep some Streamlights.

In closing, I would just like to re-iterate these are my opinions and my opinions alone; I have not received anything from either company. I have purchased and disassembled the lights on my own accord for the purpose of gathering and sharing knowledge. If you find this useful, please pass it along.

If you have any questions or thought I left anything out, my all means, please ask.

Pictures and comments on the X400

Body Housing, Note the Thick Stainless steel hinge and dovetailed floating rail interface

This is the forward side of the unit. The 4 holes you see drilled around battery contact opening interface with a plastic retention plate to secure the battery contact PCB. This keeps it from shifting or rotating.

Laser module. Note the heavy adjustment screws and large gauge tension spring

Selector Switch ball bearing race, The selector electronics reside here. This also seals the unit from moisture at the selector switch

Laser Components.

Logic Board, this holds the selector logic and Laser Driver (And probably some more)

Selector Switch anti-rotation cutouts

Head side Battery Contacts – Heavy Guage and tightly wound

Pictures and comments on the TLR-2

Machined Body. Notice the C-clip and sheet metal battery door lock.

Battery Door hinge side – Notice the cutout that interfaces with the battery door.

LED Diode and Driver Electronics – Ample Solder points for battery contact, and seated well.

Bezel – Large Sized O-ring

Battery Door – Large Guage wire, but not wound as tight.

Laser Module Retention Nut – The collimator is visible and would be hard to clean out

Laser Adjustment Screws – Very small and set in Brass.

Unity Tactical

Original Post
Originally posted by goteron:
After this experiment, I will be changing all of my IR TLR-2 units to IR X400 units. I will also change the TLR units I am using on “Go to” guns to X300’s. I will most likely keep some Streamlights.

Outstanding review, I think I understood about half of all of that. I've been using a TLR-1 on my pistols and my rifle and never had any issues. I agree that I like the TLR-1 switch more than the X series.

I've gotta say after seeing this I'm going to be looking at a X series light for my duty gun. I'd already decided to pick up a G2X for a new rifle light but this definitely helped push me towards a light I had avoided previously simply due to the price point.

Thanks for the effort you put into this.
I'll echo what Tacman said. Thanks for the sacrifice. You HAVE proven to me what I thought I knew. SF's are built to a higher level, at a higher price. SL's are probably sufficient but overkill has never failed me yet.

Thanks again.


"Maturity is a wonderful thing, but sometimes you just need to toss adulthood in the dumpster and go punch a guy in a Little Caesar costume."


“Americans murder with everything — with cars, with knives, with frozen fish — whatever’s at hand, we’ll kill a motherfucker with it, because he needed killing and we’re a nation of go-getters.”–Robert Brockway


Joined: 7/21/07        Location: North GA Mountains

Talk about giving back to the community. I don't see any links to a personal blog or website etc. so basically you sacrificed two high dollar, high end pieces of gear for the betterment of the forum. That's pretty selfless. Thanks for helping make Lightfighter what it is.

ALWAYS challenge authority.

The details really do matter.

goteron, thanks for the break down. It is much appreciated.


Personally, I'm interested in keeping other people from building Utopia, because the more you believe you can create heaven on earth the more likely you are to set up guillotines in the public square to hasten the process. -- James Lileks

"Be the lack of Bullshit you wish to see in the world around you."

Joined: 8/12/05 6:56 PM                        Location: Oklahoma (not by choice)

Originally posted by english kanigit:
...thanks for the break down ...

Nice comparative analysis, goteron.

There is one question I have, however; on the X400, is the mounting screw tensioned with a spring (like the TLR) or does it slide loosely when unscrewed?



                                                                                              "Hokey religions and ancient weapons are no match

                                                                                                 for a good blaster at your side."        -Cpt. Han Solo



Joined: 3/20/05 4:14 PM        Location:  North Carolina

That's what I call a deep study. Good to know about the internals of equipment.
I didn't have doubts about Surefire superiority but now it is more clear.
Outstanding job! Congratulations!

Joined: 30DEC08      Location: SPAIN

Take care, keep safe, stay frosty, brother!

Freaking bad ass review. Thanks for sharing both your understanding of the subject and your willingness to destroy your gear to find out how it works. I wouldn't break on of my old G2s to try to find out how they work. You broke many hundreds of dollars of excellent equipment to help everyone out. U da man.


It's easy to make assumptions about puppies strapped to missiles, but good science requires research.


Joined: 12-2005          Location: Central OK

Thanks for the kind words. I actually took the light apart to convert it to IR. Cheaper IR lasers would be great to have. I have converted uni-max lasers for training guns. I successfully converted a TLR-2 and now an X400. But I did completely destroy an X400 figuring out how it was designed. Now that I know, they are easy to convert.

But. I didn't want the information to go to waste. It's posted a few other places as well, but I knew it would be most useful here. I think it's already been ignored elsewhere. Should have known.

I imagine the laser is below the light for two reasons. 1st is ease of manufacture, they can piggyback the laser on an X300 without a redesign. This keeps seperate parts to a minimum and the manufacturing process simple. Second reason it to keep the bulk up high close to the light, imagine the holster you would need if you mounted an x400 upside down.

The devil is in the small details, Surefire just addresses them all well, they put the light together meaning never to have it apart. They are just hard use lights. That doesn't mean Streamlights aren't built well, you just get what you pay for. Its my belief the X400 is worth $200 more than the TLR-2. To put it simply, the profit margin is probably nearly the same on both lights, there is just more in the Surefire, design and components.

Some info I left out was the reflector design. Streamlight uses a "Orangepeel" design, typical of handheld lights, Surefire uses a really well built optical focusing cone for lack of a better word. Really high quality. Everything is really shock mounted and made for hard hard use. I imagine the Streamlight would break first on a shake table.

Let me know if anyone has any questions. And does anyone know a Surefire rep that would trade me for a box of parts.

Unity Tactical

I had been thinking about getting one of these two lights, I was leaning toward the SL. Now that I have been schooled on the fine point I think I may fork out the extra...I work around a lot of mud.

Thanks a ton, that was the best review ever, possibly most expensive too.
"Peace and stability do not come free of charge."
Peter van Uhm, Netherlands' Chief of Defense

I have taken both lights apart to their individual components, to the point of (probably) destroying my X400. I have literally had them both stripped down to the smallest component level possible with the tools available.

As soon as I saw that, I realised THIS is a Studboard review.

Well done mate!

Where we are, where we belong, where we should be.


Location: Back in Bris-Vegas, wondering at the bright lights of the big smoke

Thank you for this excellent review.

I was going to get cheap and go for price, but now I will go for quality. The phrase "You get what you pay for" always seems to be true.


“The two highest achievements of the human mind are the twin concepts of “loyalty” and “duty.” Whenever these twin concepts fall into disrepute – get out of there fast! You may possibly save yourself, but it is too late to save that society. It is doomed.”

- Robert A. Heinlein


Joined: 4/22/09          Location: WI

If someone from Surefire saw this quality write up and those it has and will convince to cross over to their product, I be surprised if they didn't hook you up with a new X400, on the quiet. They are just like that.

Personally this review just reaffirms what I always knew about Surefire's superiority in the market. Thanks for the great review.
Absolutely one of the best reviews I have ever read! Top notch and thank you for sharing.

Quick question for you or anyone else that may know. I'm currently running a Glock 17 with X300 in a Safariland 6360. Do you know if the X400 will fit in the 6360 line of holsters? Safariland doesn't list an ALS holster for the G17/X400 combo but it would be the first time they don't officially list a combination that can't be made to work.

Again great post and I hope someone from SureFire reads this and hooks you up with another X400. With how good SureFire's customer service is I wouldn't put it past them.

Be Safe!

9.11.01 Never Forget, Never Forgive

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