An actual lmg optic. Works beautifully. I believe it's a 3.4x zoom. Battery operated, feel free to check it out. Im running it on my custom a&k m249 and it actually does pretty well. Never thought id use a real optic on an airsoft gun but it's nice. Also a cool piece of army history. Will do exchanges for thermal or night vision, as well as other guns. I'd love to get another gas vector, and I have other stuff for sale or exchange as well.