The HS510C Open Reflex Circle Dot Sight has an open frame for a wide sight picture. Always on, 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, or a 2 MOA dot only at the push of a button. Better yet, the same LED projects both reticles, so no re-zeroing is necessary. Holosun HS510C Solar Power Open Reflex Sight When focussing on the target, the size of the reticle will change based on the distance between your eyes and objective lens. Parallax free optical design, with unlimited eye relief. Minimized obstruction of vision with push button controls and a streamlined housing design. Switchable circle/dot and red dot reticles. Always on unless manually turned off. Internal battery tray design. 32mm¡Á24mm open lens. Solar cell and high capacity battery provide dual power supplies. Titanium-alloyed, shock resistant protective hood. Quick release mount . Adaptable to Picatinny and Weaver rails. CNC machined with T6061-T6 housing. LED DATA Reticle 2 MOA Dot; 65 MOA Circle OPTICAL DATA Light source LED Parallax Parallax free Eye Relief Unlimited Coating Multi-layer coating for all lens. Magnification 1X ELECTRONIC DATA Battery CR2032 Battery Life 50,000 hours for circle dot at mid brightness setting 20,000 hours for single dot at mid brightness setting Brightness Setting 10 DL & 2 NV compatible MECHANICAL DATA Housing Material Aluminum Housing Finish PEO/MAO housing finish Housing Color Black Adjustment per Click 0.5 MOA ENVIROMENTAL DATA Storage Temperature -40C to 70C Working Temperature -10C to 50C Waterproof 1M DIMENSIONS Dimension 91*65*40 mm Weight 264g SKU HOLO-HS510C UPC 605930624571 Item Weight (gram) 204 Major Color Black Length 82mm Magnification 1x Built Material Metal Manufacturer Holosun Disclaimer The scope & optical sight is specially designed for Airsoft Purpose Only.