This is a Uncle Mike's Inside Waistband Holster known as the Nylon, model 7601-2.
These inside the waistband holsters are ultra thin four layer laminate that are no thicker than conventional suede leather holsters. The internal moister barrier won't transmit perspiration to the gun and the smooth nylon lining make for an easy draw. This model has the fold over Velcro retention strap.
Features:
Size 1
Left hand
Fits 3 - 4 Barrel medium autos