The Holosun HS510C Open Reflex Circle Dot Sight has an open frame for a wide sight picture. It is powered by solar cell under normal usage, and a back-up battery to supplement power requirements in low light conditions. Can be switched between a 65 MOA circle with 2 MOA dot, a 2 MOA dot only, or a 65 MOA ring only at the push of a button. The same LED projects both reticles, so no re-zeroing is necessary.Parallax free with unlimited eye relief.New advanced technology LED allows up to 50,000 hours of operation on one CR2032 battery2 MOA dot and a 65 MOA ringDot only, Ring only, or Dot and Ring reticle combinationsUnlimited field of viewTitanium-alloyed, shock resistant hoodBattery and solar poweredQD integrated