Featuring our patented SERPA Auto Lock release, the SERPA CQC Concealment Holster delivers a smooth draw, easy re-holster and unparalleled weapon security in a sleek package that is perfect for concealed carry. SERPA Auto Lock release. Passive retention detent adjustment screw. Speed-cut design for rapid draw, target acquisition and re-holster. Includes Belt Loop Platform and Paddle Platform. Fits Shoulder, S.T.R.I.K.E., Quick Disconnect and Tactical Holster Platforms.;Gun Fit- Smith & Wesson 5900 Series ;Gun Fit- Smith & Wesson 4000 Series