Switch: 1. The power switch 2. infared illumination Brightness regulation 3. Forced switch infrared lighting. Field of view: 6.4 degree. Visibility regulating range: ±5℃. OP-168 patent?a key pass?design, a switch to use very simple, convenient, gently rotating, can open the night-vision goggles, slowly rotating, easy to adjust the radiation light source device.