The model 558 features an adjustable locking quick detach mount offering instant removal. -0 68 MOA Ring w/ 1 MOA Dot Night Vision Compatible Dimensions: 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 g Water Resistant: Submersible to 33 ft./10 m Mount: 1? Weaver or MIL-STD-1913 Rail Brightness: 30 settings (10 for night vision) Power Source: AA Alkaline or Lithium Battery Battery Life: Approximately 1,000 continuous hours (Lithium) or 600 hours (Alkaline) at room temperature