The HWS EXPS2™ is an excellent choice for professionals. The EXPS3 offers true two eyes open shooting for fast target acquisition, night vision compatible settings, and a 7mm raised quick detach base for lower 1/3 iron sight co-witness. Single transverse 123 battery to reduce sight length Shortened base only requires at most 2 3/4 inch of rail space Battery cap and latch are eliminated and replaced with a simple O-ring, tethered cap; better sealing is achieved Battery compartment is now separated from the base to allow it to hover over the delta ring of the rifle Average battery life at brightness level 12 is roughly 1000 hours Night vision compatible: No Dimensions: L X W X H: 3.8" x 2.3" x 2.9" (96.5 x 58.4 x 73.7 mm) Weight: 11.2oz (317.5g) Water Resistant: 33ft. (10 m) depth Mount: 1" Weaver or MIL-STD-1913 rail Windage & Elevation Adjustment: 0.5 MOA per click Brightness: 20 daylight settings, 10 additional settings for Gen I through III+ night vision devices Power Source: 1 x CR123 battery Battery Life: 1,000 continuous hours at nominal setting 12 at room temperature Operating Temperature: -40°F to 140°F (-40°C to 60°C) Country of Origin: Made in USA