The Firefield 30mm fixed mount is a cantilever mount constructed of durable 6061-T6 aluminum. As a cantilever mount, this unit is designed to be used with rifles with high recoil cartridges, since they provide extra clearance between the shooter&';s eye and the rear of the scope, allowing for a comfortable and safe eye relief distance. By extending the scope forward over the rifle&';s action, the Firefield 30mm fixed mount may help shooters achieve better balance and a more natural shooting position. This is good for scopes with large objective lenses. Included in Package Hex key Features Made from durable 6061-T6 aluminum Matte black, no reflective finish 47mm/1.85in forward offset Fixed mount design Fit 30mm riflescope tubes