Compact accessory rail clamps directly to the scope tubes to provide mounting space for holographic sights, lasers, IR illuminators, flashlights, and other accessories that fit Picatinny style rails. Increases accessory mounting options, without restricting your scope base and ring options. Install on 30mm Top rail length: 45mm (1.8 inch), ring length 18mm (0.7 inch) Weight (net): 28g (1.0 ounce) High quality aluminum alloy Can assemble laser, flashlight and red dot sight Can mount either side of the scope Easy to use without special tools With 30mm to 25.4mm (one inch) adapter