The EOTech EXPS2 Transverse Law Enforcement and Military Holographic Red Dot Sight is the shortest model available from EOTech. It runs on a single CR123A battery which provides up to 600 hours of continuous runtime at setting 12. The EXPS leaves tons of rail space available for mounting flip-up iron sights or a magnifier and the integral mount allows for use on either a Weaver or Picatinny-style rail. The EOTech EXPS2 is not compatible with night vision devices. FeaturesMaximizes rail space with its compact size and allows for co-witnessing of iron sightsIt has convenient side buttons to add a magnifierAdjustable, locking, quick-detach lever for easy attachment and removal