Eotech has done it again by making the best even better. Offering true 2 eyes open shooting, a transversly mounted lithium 123 battery, and 7 mm raised base offering iron sight access, the new Extreme-XPS (EXPS) features easy to adjust side buttons and an adjustable, locking, quick detach lever for easy attachment and removal. Product Details Single transverse 123 battery to reduce sight length Shortened base only requires at most 2 3/4 inch of rail space Battery cap and latch are eliminated and replaced with a simple O-ring, tethered cap; better sealing is achieved Battery compartment is now separated from the base to allow it to hover over the delta ring of the rifle Average battery life at brightness level 12 is roughly 500-600 hours Side buttons, NV compatible with an adjustable, locking, quick detach lever for easy attachment and removal Product Specifications Magnification: 1x Eye Relief: Unlimited Length/Width/Height (inches): 3.5 x 2.4 x 2.8 (91.4X 60.9x71mm) Weight: 11.2 oz (317grams) Temperature: -40 to 150 F Waterproof: Submersible to 33 ft depth Sealing: Fogproof internal optics Adjustment (per click): 0.5 MOA (1/2 inch at 100 yds) Adjustment Range: +/- 40 MOA travel Mount: 1 in. Weaver or (MIL-STD-1913) rail. Adjustable for width variation Return to Zero: Repeatable to within 2 MOA after re-mounting Night Vision Compatibility: 10 brightness setting (generation I-III+) Heads-Up-Display Window Optical Surfaces: Anti-glare coating Window Dimensions (inches): 1.20 x 0.85 (30 x 23mm) Front Window Material: 1/8 inch solid glass Rear Window Material: Shatter resistant laminate (3/16 inch thick) Field of View (100 yds): 30 yds (28m) at a 4 inch eye relief Electrical Brightness Adjustment Range: 146,000:1 brightest to lowest Night Vision Brightness Range: 1280:1 with NV switch engaged Power Source: (1) 123 lithium battery Battery Life: 600 continuous hours at nominal setting 12 Brightness Settings: 30 settings with scrolling feature (10 settings for NV use) Auto Battery Check Indicator: Flashing reticle upon start-up Auto Shut-down: At 8 hrs- programmable to 4 hrs