The MBUS (Magpul Back-Up Sight) Pro is a corrosion-resistant all-steel back-up sighting solution that delivers maximum functionality and strength with minimum bulk at a price that's even smaller than its size. The dual aperture, windage adjustable rear and no-tool, elevation adjustable front excel in all 1913 Picatinny rail mounting applications, including rail-height gas blocks. Positive detents keep the MBUS Pro Front and Rear at standard AR sight height when deployed, and so low when they are stowed that you'll never notice them until they're needed. Narrow width front sight is compatible with most IR aiming laser and light installations for the professional user. Product Specifications Position: Front Height above rail, stowed: ~0.43 in. max Length, stowed: 1.6 in. Weight: 1.5 oz. Compatibility: Mounts on any MIL-STD-1913 Picatinny/STANAG 4694 rail including receiver-height gas blocks. Elevation Adjustment: ~1 MOA (1.131"/100m) per click with a 14.5" sight radius Elevation Adjustment: ~0.7 MOA (0.820"/100m) per click with a 20" sight radius Origin: Made in the USA