The Burris AR-P.E.P.R. Scope Mount is perfect for mounting your scope forward on your AR-style rifle. The Proper Eye Position Ready (P.E.P.R.) Mount provides 2" of forward scope positioning room which will allow you to obtain proper eye relief and maintain a proper shooting position. Includes both smooth and picatinny ring tops. * 34mm model features 20 MOA elevation built in. Additional Specifications: Height A (from rail to bottom of scope ring) :1" = 1.0"30mm = 1.0"34mm = 0.68" Width B (rings) :1" = 1.57"30mm = 1.75"34mm = 1.90" Height C (from rail to middle of scope rings) :1" = 1.5"30mm = 1.6"34mm = 1.35" Length D (front of front ring to back or rear ring) :1" = 4.15"30mm = 4.15"34mm = 4.92" Length E (between rings) :1" = 2.15"30mm = 2.15"34mm = 2.9"