UTG PRO 30mm/2PCs High Profile P.O.I Picatinny Rings Black. O.I (Precision Optics Interface) Picatinny Scope Rings. Aluminum and Steel Construction Integral Squared Recoil Stop Low Profile Torx Locking Side Plate with Dual Spring Loaded Guide Rods Precision Machined Inner Ring Surface 4 Torx Screws 30mm Diameter 30mm Center Height 22mm Width Specifications for UTG PRO 30mm/2PCs P.O.I Picatinny Rings: Manufacturer: UTG Pro Tube Diameter: 30 mm Ring Quantity: Pair Fabric/Material: 6061-T6 Aluminum Alloy / 4605 Steel Condition: New Color: Black Attachment Type: Picatinny Package Contents: UTG PRO 30mm/2PCs P.O.I Picatinny Rings UTG PRO RWU013022: 30mm/2PCs High Profile P.O.I Picatinny Rings Black