Ultimate Arms Gear Tactical Aluminum Automatic Deploy Weaver Picatinny Rail Rifle Shotgun Front And Rear Combo Set Flip Up Backup A2 Post Back Up Iron Sight Mount Flip-Up Front and Rear Sight Towers Complete with A2 Post Assembly with Locking Retention and Precision Elevation Adjustments for Greater Accuracy Mounting Decks Designed to be used with Handguard & Flattop both will fit all 7/8-Inch Picatinny/Weaver style Easy Quick and Secure Installation -Allen Screw Locking Clamp Rail Base Retention For Maintaning Zero Under Heavy Conditions Windage and Elevation Adjustable Slim Design for Low Profile Silhouette when Stowed