This is a Burris Picatinny Style 1/2" Riser Block Mount. Great for any AR-15 Flattop. Raises mounting surface by 1/2", mounts to existing Picatinny style rail. Solid anodized CNC machined aluminum. Easy to install without modification. Length is 1 1/2". Flat matte finish, attaches with two hex head screws, hex wrench is included. Riflescope mounting applications require two riser block mounts. Forever warranty from the manufacturer.