The Holosun HE503CU-GR Elite is a new micro green dot optic equipped with a 65 MOA circle dot reticle with the option of switching to a 2MOA dot only. Holosun's highly efficient light emitting diodes and solar panels allow Holosun solar optics to run without a battery in many lighting conditions. Additionally, the back-up battery lasts up to 5-years on the dot and up to 2 years on the circle dot. The U signifies a housing design that shrouds the windage and elevation turrets on two sides. Parallax free with unlimited eye relief.New advanced Green technology LED allows up to 50,000 hours of operation on one CR2032 battery2 MOA dot and a 65 MOA ringUnlimited field of viewParallax-free with unlimited eye reliefPowered by both battery and solarLow mount and 1/3 Co-witness mount included