This is a Galco Belt Holster known as the DAO, model DAO186.
The DAO(TM) can be worn strong side or crossdraw at the user's discretion. The holster employs a retention strap for simplicity and security in the brush. The retention strap has a large polymer tab to aid in snapping and unsnapping with a gloved hand. Tension screw adjustments allow for a custom fit to your revolver. Constructed of premium saddle leather" the DAO fits belts up to 1 3/4".
Features:
Premium steerhide
Adjustable tension unit
Retention strap with glove-friendly polymer tab
Can be worn strongside or crossdraw
Fits belts up to 1 3/4"