The EXPS2 offers true 2-eyes-open shooting and provides an unparalleled targeting experience. The all-purpose EXPS2 features easy-to-adjust side buttons and a quick-detach lever. It has a transversely-mounted lithium 123 battery. The increased height of the EXPS provides iron sight co-witness access in the lower third of the viewing window. Whether you&';re using the sight for law enforcement or hunting, the EXPS series sights are the premier optics in the line. Quick-detach lever fits both 1" Weaver and MIL-STD-1913 rail Battery life 600 continuous hours at nominal setting 12 at room temp EXPS2-2 reticle