Magpul Extended Rubber Butt Pad Comes standard with the CTR and MOE Commercial-Spec stocks Utilizes a firm rubber that is designed for enhanced shoulder purchase and improved impact/drop mitigation May also be used with the Mil-Spec models as well as all STR, ACS-L, ACS and UBR stocks for 0.25" increased length-of-pull All mounting hardware included; Made in USA NOTE: Not compatible with MOE Fixed Stock