Competition 45 Auto parts. Shok Buff Recoil System. Guide rod controls the recoil spring to keep from kinking. Polyfiber buffers prevent the slide from pounding the frame, softer recoil, and more consistant barrel lock up - resulting in improved accuracy. Package includes: 6 Shok-Buff Buffers, 1 - 416 Stainless one piece guide rod & plug, 1 extra power firing pin spring, 1 extra power heavy duty recoil spring (20 *# EP), 1 reduced power heavy duty recoil spring (12# RP). WS64 Fits Colt/LW/Combat Comm., 1991 A1 Commander, Detonics Servicemaster, Para Ordnance P-13