Efficiency in red-dot optics has advanced tremendously in recent years, leading to cutting-edge optics like the Holosun HS503CU Solar Micro Circle Dot Sight. This red-dot optic provides firearm enthusiasts with a powerful, durable, long-lasting sight that they can count on in any environment. The Holosun HS503CU Solar Micro Circle Dot Sight is built with the company's high-efficiency LED electronic system, which draws only a minimal power charge. Combined with this system are built-in solar panels on the exterior of the optic's housing, enabling the sight to run without depending on a battery in the right lighting conditions. The Holosun HS503CU Solar Micro Circle Dot Si Mfg: Holosun