The HS403C is a solar version of the successful HS403A. Our 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. The HS403C is compatible with standard mounts. Features; Designed for day and night use; New advanced technology LED allows up to 50,000 hours of operation on one CR2032 battery; 2 MOA on dot size; Reduced training time and ammunition; Unlimited field of view; Parallax-free with unlimited eye relief; Unaffected by extreme weather conditions; Low mount and 1/3 Co-witness mount included.