Ultimate Arms Gear Tactical 12 Slot Dovetail 3/8" 11mm To Weaver - Picatinny 7/8" .22 Rife Airgun Crossbow Adapter Mount Provides A 12 Slot 4.92" (125 mm) Long Weaver/Picatinny Standard 7/8" Accessory Rail Made Of Aircraft Grade Aluminum Alloy With Black Matte Finish Simple To Install - Just Attach To Your 3/8" (11mm) Dovetail Rail To Transform It Into A 7/8" Weaver Picatinny Rail Allows You To Attach All Your Weaver Picatinny 7/8" Base Accessories : Scopes, Lights, Lasers, Rings With A Visible Line Of Sight Perfect For Airguns - Paintball - Airsoft - .22 Rifles Or Other Dovetail Based Weapons