The HWS EXPS3 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. Product Specifications 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