Q45H/64 model is a Multi-fuction monitoring system, it can be used for monitoring of testing ozone in ... continuously. 1,Q45H/64 model is a Multi-fuction monitoring system, it can be used for monitoring of dissolved ozone in ... water continuously.the user can choose system range:0-200.0ppb,0-2.000ppm or 0-20 ... is 0-55. 2,photos of factory online automatic ozone test system