Our AR15 butt pad is made of non-slip rubber for Wear Resistance & Durability. It features horizontal grooves to grip and is concave to hold the stock securely to prevent it from slipping. It helps reduce recoil by 40% and Increases your length of pull. Compatible only with Magpul CTR, MOE & PTS stocks. Easy Installation - Simply slips on stock's rear. No gunsmithing is required.