Product Description While originally used with the AK family, this stock is beginning to be seen on American manufactured assault rifles, such as the M4, and is a functional and durable addition to any paintball marker. This stock will fit the Tippmann 98 Custom, Custom Pro, 98 Custom with ACT, and the Custom Pro with ACT. It is made out of aircraft grade aluminium even the butt plate. Also has a rear velocity adjuster with thumb screw. The stock is 11" long and Made by Ultimate Fusion Designs.