Perfect for anyone that doesn t like to sacrifice. The 558 is compatible with all Gen-I-III night vision devices and features an adjustable, locking quick detach mount that offers instant removal. The operational buttons are located on the side of the sight making this optic ideal for use with EOTech switch-to-side magnifiers. The drop-in replacement Laser Battery Caps (LBC and LBC2) are designed to work with this model as well, increasing your aiming capabilities and speed to target all day and night long. Specifications Length/Width/Height: 5.5 x 2.2 x 2.8 (140 x 56 x 71 mm) Weight: 13.3oz (377 g) Water Resistant: Submersible to 33 ft. (10 m) depth Mount: 1 Weaver or MIL-STD-1913 rail Brightness: 20 daylight settings 10 additional settings for Gen I through III+ night vision devices Power Source: Two 1.5 V AA batteries Supports lithium, alkaline, or rechargeable Battery Life: Lithium: 1,000 continuous hours at nominal setting 12 AA alkaline: 600 continuous hours at nominal setting 12