Shenzhen Guangyang Zhongkang Technology Co., Ltd , https://www.lighttherapymachine.comTD826-M4 portable multi-gas detector main functions and features: â— small size, portable, sturdy, audio sound, light alarm indication â— large screen digital display â— boot sound and light vibration alarm function self-test â— safety tips: regular flashing lights , voice prompts â— upload computer function (optional) â— product is simple to use, easy to operate, low maintenance costs â— can support 1, 2, 3 or 4 kinds of gas real-time detection of the main technical parameters: â— transmission sensor: Electrochemical / Catalytic â— Electric?? Pool: 3.7V2000MAh Lithium-ion rechargeable battery, please download the details.