Ultimate Arms Gear Tactical Machined Aluminum QD Quick Detach Weaver - Picatinny 7/8" To Dovetail 3/8" 11mm Rail Adapter Mount Made From Aircraft Grade Aluminum - Black Anodized Convert Your Weaver/Picatinny (7/8") Rail Base Into A Dovetail (3/8") Base So You Can Use Your Favorite Dovetail Accessories Easy Installation - "QD" Quick Detach Thumbnut 1.2" Length