This is a Trijicon Magnifier known as the MROHDMAG, model MAG-C-2600001.
For decades" Trijicon Optics have earned the trust of military" law enforcement" hunters and shooting enthusiasts. Every optic is built with legendary toughness" precise adjustability and outstanding" high-quality glass that gives the user the accuracy they need to get the job done with confidence.
Features:
3X Magnifier
Quick Release
Flip to Side Mount