This is a Maxpedition Holster known as the CCW, model 3501B.
The Universal CCW Holster is an ambidextrous holster that fits most handguns. It attaches with hook side Velcro to loop Velcro sewn in various Maxpedition packs. The 2" retention strap can be adjusted for a snug fit around your weapon.
Features:
Spine has an adjustable 2 retention strap;Positions securely in the CCW compartment of most Maxpedition bags