This sight is smaller than the former n-cell batter sight (511/551) and it is waterproof to 10 meters.It runs on a single cr123a battery and it has a longer battery life than the n-cell style sights.With the single battery configuration the xps allows more rail space than ever leaving more room for rear iron sights or nv mount.Smaller lighter and always fast; the xps series is a great addition.This holographic weapon sight is night vision compatible with up to 10 settings for nv use.Battery: CR123AMagnification: 1xObjective: 30x23mmField Of View: 30 yds @ 4" Eye ReliefEye Relief: UnlimitedDot Size: 1 MOALength: 3.80"Weight: 9 ozFinish: BlackReticle: 68 MOA Ring/2 1 MOA Red DotAdjustment Size: .5" @ 100 ydsProofs: Water Resistant/FogproofOptic Coating: Anti-ReflectionWindage Elevation: 40 MOA