The 407K-X2 is an open reflex sight designed for concealed handgun applications. Features Holosun’s Shake Awake technology to activate the LED at the slightest detection of movement and deactivate the LED during periods of motionless. The 407K-X2 has 10 daytime brightness levels and 2 night-vision compatible levels. 50,000 hours of battery life on setting 6 means you won’t be changing batteries often, but when you do need a replacement, the convenient battery tray allows the user to swap batteries without removing the optic from the slide. This optic is parallax-free and has unlimited eye relief. The Holosun 407K-X2 is IP67 waterpoof rated.