This is a EOTech known as the 518, model 518.A65.
The best just got better. The 518 runs on easy to find AA batteries but offers all of the features found in EOTech's EXPS top of the line sight. With side button functionality you can reduce rail space when partnering the 518 with an EOTech magnifier. The 518 is also compatible with the new drop-in Laser Battery Caps that EOTech designed to enhance aiming through the use of visible and IR lasers.
Features:
Water Resistant
Fits weaver or MIL-STD-1913 rail
Supports lithium, alkaline, or rechargeable AA batteries
20 daylight settings
