This is a Sightmark Red Dot known as the Element, model SM26041.
The Sightmark Element Mini Solar red dot provides dependability on the highest level" allowing for continuous use from reliable battery or solar power. With up to 200"000 hours of battery life from a single CR2032 and the ability to run off top-mounted solar cells" the dual-power Element Mini Solar's 3-MOA red dot reticle stays on in virtually any environment. When tactical situations get intense" don't fumble with buttons to adjust brightness. The Element features an innovative Eclipse Light Management System" which automatically adjusts reticle brightness based on the light of your surroundings. Taking innovation a step further" the Element has a hinged battery door and protected adjustment caps that double as adjustment tools for the windage and elevation. All Element Mini Solar red dots come standard with flip-up lens caps" a low picatinny mount for shotguns and certain rifles" an absolute cowitness mount for AR firearms and Sightmark's Lifetime Warranty.
Features:
Dual power ability – battery or solar power
Eclipse Light Management System
Adjustable mount height – two mounts included
3 MOA red dot reticle
Unlimited eye relief
Protected adjustment caps doubling as adjustment tools
1x22 objective lens
Flip-up lens caps included