UTG Flip-up Rear Sight w/Windage Adj & Dual Aiming Apertures Flip-up tactical rear sight from UTG includes dual aiming aperture Dual aiming apertures for all shooting applications; precise windage adjustments Unique Posi-lock feature prevents tipping; user-friendly locking thumbnut for easy installation Aluminum construction; accepts both Picatinny and Weaver mounts; 3.4-ounce weight; measures two by 1.9 by 1.3 inches (W x H x D) Includes limited lifetime manufacturer's warranty