The HE508T-GR-X2 green dot sight from Holosun is a pistol-sized optic with an open frame and clear sight picture. This premium optic features an ultra-durable Grade 5 Titanium housing that is up to 5 times the strength of 7075 aluminum and is able to withstand seawater. Holosun’s Multiple Reticle System (MRS) gives the user three different green reticle options including a 32 MOA circle with 2 MOA dot, a 2 MOA dot only, or a 32 MOA ring only. This sight is powered by a high-capacity CR1632 battery to power the LED for up to 100,000 hours and features a convenient side access battery tray, allowing the user to change the battery without removing the optic. In the event you do run out of battery, this optic features Solar Failsafe technology to power the optic when used in sunlight. Holosun also designed this optic with Shake Awake technology that senses motion to power the LED on and off, and a last setting recall that ensures you don’t lose your custom settings when the unit powers down. This optic is parallax free and has unlimited eye relief. IP67 waterproof rated.