Marble's Improved Tang Peep Sights are capable of satisfying the requirements of both short and long range shooters. The sight's modular base may be permanently attached to a rifle's tang, and incorporates a setscrew to release the upright post/aperture combination for replacement with any of 4 incrementally taller upright posts, allowing for accurate target engagement up to 1000 yards when outfitted with the long range post option. CNC machined components guarantee that parts mate perfectly for repeatable accuracy. Sight includes a gun-specific modular sight base and an Allen wrench only. Upright posts (short-range, standard, mid-range or long-range) and different aperture sizes are available separately. Notes:Requires the correct mounting screw set for use, an upright post and an aperture (all sold separately). See other fits in specs below