The HS510C Open Reflex Sight with Circle/Dot Red Reticles has an open frame for a wide sight picture. It is powered by a CR2032 batter with Holosun's innovative Solar Failsafe back up. Equipped with Multi-reticle system, the red reticle 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. Better yet, the same LED projects both reticles, so no re-zeroing is necessary.