This is a BLACKHAWK Belt Holster known as the CQC, model 410567BK-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 a passive retention detent adjustment screw. Rapid draw" target acquisition and reholstering are improved with the speed-cut design of the holster. They fit Shoulder" S.T.R.I.K.E." Quick Disconnect and Tactical Holster Platforms.
Features:
Includes Belt Loop Platform and Paddle Platform
SERPA Auto lock release
Distinctive and unique L shaped button
Left hand
Fits Glock 42