The helmets pictured are a U.S army ACH with a 3 colour desert cover on the left and on the right is a Canadian Forces CG634 which are pretty hard to find in the U.S :b The ACH is made made of Kevlar nothing super special ,the U.S has been using Kevlar since the mid 80’s with the PASGT helmet. But the CG634 is interesting because it’s made out of spectra fiber which supposedly has a longer shelf life and some better ballistic protection than Kevlar ,the down side to spectra though is it’s price. It’s interesting to learn that while the U.S was dicking around with the PASGT in the 80’s and 90’s the Canadians had come out with a composite helmet ahead of it’s time. But if it’s not broken why fix it both of these helmets still see service in their countries militaries arguably the ACH sees more service worldwide but whatever :b