LaRue Tactical LT139 SPR-3 QD Rifle Scope Mount Places the centerline of the optic 1.5" above the top of the rail Eliminates the need to span from the receiver to the handguard Provides a more robust platform for the optics, increases repeatability and eliminates the need for time-consuming lapping Precision-machined out of bar-stock aluminum Provides outstanding return to zero; the optic can be removed and replaced without loss of zero