The HS515GM is a micro red dot optic equipped with a 65 MOA circle dot reticle with the option of switching to a 2MOA dot only. The G signifies that the battery is side mounted on the side of the optic. Employing new LED technology, the life-time for one CR2032 battery can reach 5 years on the 2 MOA dot. Holosun’s Shake Awake technology automatically turns the optic on at the slightest movement. When the optic senses no movement, it will go to sleep. This product includes clear flip-up lens covers, a quick release mount and a kill flash filter.