Blue Force M16 Buttstock Adapter - Coyote Brown Tex 90 bonded nylon thread  never had a sling returned for stitching failure INVISTA Solution Dyed CORDURA webbing  low IR, soft enough for all day comfort but sturdy enough to prevent rolling Glass reinforced DuPont Zytel Nylon hardware Super 90 bar tack stitching for extreme durability in combat conditions