JTM Sports Tactical Smart Polymer Picatinny/Weaver Front and Rear Combo Set Flip Up Backup AR15 AR-15 M16 M4 M-4 Flattop A1 A2 Post Back Up Sight non Imported High quality flip-up front and rear sight towers complete with A2 square post assembly with locking retention and precision elevation adjustments for greater accuracy. Mounting Decks designed to be used with handguard rails or front gas blocks (front sight tower) and both will fit all 7/8" Picatinny/Weaver style rails Allen Wrench With Locking Retention For Maintaning Zero Under Heavy Conditions Easy And Quick Installation