Mounts to rifle-length receiver extension tube without A2 spacer; Will also accommodate mil-spec sized M4 Carbine and many A5-length tubes with standard Castle Nuts and End Plates (not included); Enhanced strength butt-plate withstands severe impact and recoil up to .50 BMG; Rubber butt-pad provides positive shoulder purchase to prevent slippage and is adjustable for both cant and height; Machined aluminum LOP and Cheek Piece adjustment knobs with positive locking click detents; Steel adjustment shafts finished with Melonite for wear and corrosion resistance; All aluminum components finished with MIL-A-8625F, Type III, Class 2 hard anodizing; Bottom M-LOK slots provide additional sling mounting possibilities or for attaching 1913 Picatinny rails for use with a monopod; Made in U.S.A.; Black Finish