Vortex Cantilever Rifle Scope 30mm Ring Mount allows you to equip and properly use a rifle scope on your AR-15 flat top rifle. These Vortex ring mounts feature a two to three-inch offset orientation, which allows you to install your telescopic sight in a forward location. With its offset position, you can maintain the correct head placement and eye relief when looking through the rifle scope, impossible on the AR-15 with a straight mount.