Customers came to us to buy the portable gas detectors. After disscusion with him, we found they need to detect CO2 O2 NO2 NO H2S and flammable gases in the coal mines 24 hours online to make sure the safety.Hence we suggest customers our YT-95H-A series gas detectors to install inside the mines and our YT-1000H-Z controller to install outside the mines to view the data online. YT-1000H-Z controller is touch screen which is easy to operate and it can connect and control more than 60 pieces gas detectors.