Machined from heavy-duty aluminum alloy, the Triple Rail Scope Mount provides shockproof performance. Built-in weaver/Picatinny rails allow installing different accessories. Durable matte black finish can withstand extreme conditions. The Triple Rail Scope Mount works with real fire calibers. Technical Details: · Aluminum alloy construction · Shock-proof performance · Ideal for 21mm Weaver/Picatinny rails · Matte black finish · Item dimensions: 25.4mm L x 35mm H x 30mm diameter · Item weight: 7.6-ounce