Holosun Technologies Open Reflex, 2MOA Dot or 2MOA Dot with 65MOA Circle, Solar with Internal Battery, Quick Release Mount, AR Riser, Protective Hood, Black Finish HS510C The 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. The 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.