The Burris P.E.P.R. mount is an incredibly solid, long-lasting cantilever mount. It makes mounting an optic to an AR-style rifle very easy, providing the necessary clearance and adding as much as 2 inches of forward scope positioning. It also ensures proper eye placement -- in fact, P.E.P.R. stands for "Proper Eye Position Ready"Features:Allows up to 2 inches of forward scope positioning;Provides optimum eye relief and full field of view;Includes both smooth and Picatinny ring tops