Trust the Holosun Hs507K-X2 Multi Reticle Reflex Sight in the field. This open reflex optical sight is designed for concealed carry pistol applications and has a IP67 waterproof construction for long-lasting use. The Lock Mode locks the buttons to prevent inadvertent setting changes, while the Shake Awake technology shuts the LED off during periods of motionlessness but instantly reactivates when you move.