HURRICANEHolo Sight - (TAN) Beautiful full metal holographic sight is a replica of the popular military EO-tech sight. This sight is digitally adjusted and can be set to either red of green sights. Key features include: - Red & Green dot color changeable (digitally). - 20 level brightness adjustment. - Low power indicator. - 2 hours auto shut down. - UV tempered lens. - Moisture Resistant design. - Battery: LR44 Alkaline button cell x 4. - Full metal construction Operates just like the EOTECH sight. Press the UP button and the unit turns on. Press the UP and DOWN buttons to adjust intensity, or the middle W button to change between red and green holographic pattern. Press both buttons at the same time and the unit will turn off. Perfectly designed for the M4 - install this sight onto the flat-top rail of your M4 - your M4 / M16 front sight will NOT obstruct the holographic image since its located high enough to look over the top of the front sight.