The EOTech 556 Law Enforcement and Military Night Vision Holographic Red Dot Sight is ideal for use with magnifiers or night vision devices. This sight features the button operation on the side rather than the front making it much more convenient for the user. The base of the sight is designed to clear the delta ring and handguard on M4 style weapons which reduces the amount of rail space needed for mounting. 

Technical Information (From the Manufacturer)
• Optics: Transmission holography - parallax free
• Magnification: 1x
• Eye Relief: Unlimited
• Length/Width/Height: 5.1" x 2.1" x2.8"
• Weight: 11.9 oz
• Temperature: -40 to 150 F
• Waterproof: Submersible to 33 ft depth
• Sealing: Fogproof internal optics
• Color/Finish: Non reflective black with hard coat finish
• Adjustment (per click): 0.5 MOA (1/2" at 100 yds)
• Adjustment Range: +/- 40 MOA travel
• Mount: 1" Picatinny (MIL-STD-1913) rail
• Return to Zero: Repeatable to 1 MOA after re-mounting
• Optical Surfaces: Anti-glare coating
• Window Dimensions: 1.20" x 0.85"
• Front Window Material: 1/8" solid glass
• Rear Window Material: Shatter resistant laminate (3/16" thick)
• Field of View (100 yards): 30 yards (28m) at a 4" eye relief
• Standard Reticle: A65/1
• Night Vision Brightness Range: 1000:1 with NV switch engaged
• Function Button Location: Left side near the rear of sight
• Power Source: 2x 3.0V Lithium 123 batteries
• Battery Life: 1,000 continuous hours (lithium) 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

Model : 556