The model 558 features an adjustable locking quick detach mount offering instant removal.-0 68 MOA Ring w/ 1 MOA DotNight Vision CompatibleDimensions: 5.6"L x 2.2"W x 2.9"H (142.3 x 55.9 x 73.7mm)Weight: 13.8 oz / 391.2 gWater Resistant: Submersible to 33 ft./10 mMount: 1" Weaver or MIL-STD-1913 RailBrightness: 30 settings (10 for night vision)Power Source: AA Alkaline or Lithium BatteryBattery Life: Approximately 1,000 continuous hours (Lithium) or 600 hours (Alkaline) at room temperature