Higoo 2PCS 30mm Medium Profile Riflescope Rings, Picatinny/Waver Scope Ring Mount Precision Machined from Aircraft-grade Aluminum Alloy with Anodized Black Matte Finish. Fits 20mm Picatinny/Waver Rail, Ring Diameter: 30mm Friendly Hex Screws, Wrench, Easily install and remove with 20mm rail on its top 2PCs In One Package