This is a BLACKHAWK Belt Holster known as the CQC, model 410500BK-L.
Featuring their patented SERPA Auto-Lock(TM) technology" the SERPA CQC Concealment Holster delivers a smooth draw" easy re-holster and unparalleled handgun security in a sleek package that is perfect for concealed carry.
Features:
Passive retention detent adjustment screw
Includes Belt Loop Platform and Paddle Platform
Fits Shoulder, S.T.R.I.K.E., Quick Disconnect and Tactical Holster Platforms
Left handed
Fits Glock 17/22/31