Feature a Flexible Cant Options: 0 MOA for Standard Distance Shooting, 20 MOA Cant Provides Extra Elevation for LongRange Shooting a Secure Scope Clamping: Four Screws per Ring Keep the Scope Firmly Mounted for Stable and Repeatable Accuracy a Optimal AR Sight Height: 38mm/1.5in Height from Base to Ring Center Supports Comfortable Eye Alignment on AR Platform Rifles a Strong Picatinny Interface: 21mm Picatinny Mount with Dual Crossing Bolts Ensures a Solid and Reliable Rail Connection a Recoil-Resistant Design: Anti-Retreat Bar Prevents Mount Movement Under Recoil for Consistent Shooting Performance What are 0 MOA and 20 MOA?0 MOA: A 0 MOA mount does not have any built-in elevation. When a scope is mounted on a 0 MOA mount, the optical axis of the scope remains parallel to the barrel of the firearm. This means that the scope&';s reticle is aligned with the bore axis, and no additional upward or downward adjustment is introduced.20 MOA: A 20 MOA mount, on the other hand, has a built-in upward cant or angle of 20 MOA. When a scope is mounted on a 20 MOA mount, the optical axis of the scope is angled slightly upward relative to the bore axis. This introduces additional elevation in the scope&';s point of impact. The purpose of a 20 MOA mount is to provide increased elevation adjustment capability for long-range shooting or compensating for bullet drop at extended distances. Size Specifications Specification Details Ring Dia: 30 mm Height: 62 mm / 2.4 in Central Height: 38 mm / 1.5 in (Bottom to Center) Length: 139 mm / 5.5 in Material: 6061 - T6 Aluminum Alloy Weight: 155 g / 5.5 oz Mount: Picatinny Finish: Black Matte / Coyote FDE Items in the Package: T15 Torx Wrench, Retail Package Video