I bought my ACH off an airsofter and it came with a fake crye printed cover that I replaced with a legit ACU cover- With 20 minutes of spare time I managed to get it cut down to fit another 20 mins to hand sew the velcro patches on the inside of the cover (the machine's needle didn't like getting gummed up with the adhesive on the back of my velcro)
The helmet itself only required two new patches of loop velcro on either side of the NODs mount because of the pre-existing velcro on it-
