Ultimate Arms Gear Glock Black Large & Small Grip Back Strap Adapter with Locking Pins fits Compact & Standard Glock Frames Gen 1 2 3 Models 17, 19, 22, 23, 24, 31, 32, 34, 35, 37, 38 Adapter Fit Standard and Compact Glock Frames GEN 1, 2, & 3 Series Models: 17, 19, 22, 23, 24, 31, 32, 34, 35, 37, 38 The Adapter Goes to the Back Strap of the Glock Frame, Permitting the Shooter's Hand to Conform to the Frame in a More Secure Manner. Offers More Control and Allows the Shooter to Index on Target More Efficiently. Color: Black. Size: Small & Large. Locking Pin Included.