This adapter plate mounts directly to the pistol using the fasteners provided with the mount. The Trijicon RMRcc is then mounted to this adapter using the Trijicon supplied fasteners. Fits All Smith & Wesson M&P, Shield C.O.R.E models, Springfield Hellcat OSP, Springfield XDS Optics Ready, Glock 43x MOS, and 48MOS, Ruger Max-9 Optics Ready, Mossburg MC2 SC, SCCY CPX1, and CPX2 Optics Ready. This mount fits most Shield RMSc cut pistols.