Review of the Eotech 512 holographic weapon sight. Here are the specs from the Eotech website.
Optics: Transmission holography – parallax free
Magnification: 1x
Eye Relief: Unlimited
Length/Width/Height: 5.4″x2″x2.25″ (137×50.8×57 mm)
Weight: 10.9 oz (309 grams)
Temperature: -40 to 150 F (using AA lithiums); -20 to 140 F (all other battery choices)
Waterproof: Submersible to 10 ft depth
Sealing: Fogproof internal optics
Adjustment (per click): 0.5 MOA (1/2″ at 100 yds)
Adjustment Range: +/- 40 MOA travel
Mount: 1″ Picatinny (MIL-STD-1913) or Weaver rail
Return to Zero: Repeatable to 1 MOA after re-mounting
Heads-Up-Display Window
Optical Surfaces: Anti-glare coating
Window Dimensions: 1.20″ x 0.85″ (30 x 23mm)
Front Window Material: 1/8″ solid glass
Rear Window Material: Shatter resistant laminate (3/16″ thick)
Field of View (100 yds): 30 yds (28m) at a 4″ eye relief
Electrical
Brightness Adjustment Range: 110,000:1 brightest to lowest
No Night Vision Compatibility
Power Source: 2x 1.5V AA batteries (supports lithium, alkaline, or rechargeable)
Battery Life: 1,000 continuous hours (lithium) at nominal setting 12; 600 continuous with AA alkaline
Brightness Settings: 20 settings with scrolling feature
Auto Battery Check Indicator: Flashing reticle upon start-up
Auto Shut-down: At 8 hrs- programmable to 4 hrs
That's the fake one.