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.Specifications and Features: Magnification: 1x Eye Relief: Unlimited Length/Width/Height: 3.5x2.4x2.4in Weight: 8 oz Temperature: -40 to 150 F Waterproof: Submersible to 10 ft depth Adjustment (per click): 1/2 MOA Adjustment Range: +/- 40 MOA travel Return to Zero: Repeatable to 2 MOA after re-mounting