BLE-9909 Water Quality Pen: 3 in 1 Bluetooth PH/TDS/EC/Salinity/Temperature with Backlight1. Multi-function meter with Bluetooth: smart mobile phone APP control, mobile phone full-screen multi-parameter display, professional PH/TDS/EC/salt and temperature measurement. The mobile phone can control the backlight. Drinking water, fish tank, fish tank, swimming pool, farmland irrigation, laboratory, etc. 2. Cloud-based data management system: Bluetooth real-time precision data transmission, synchronization of time and data records, data sharing or Excel chart printing, mobile phone can view the calibration record.3 . Automatic calibration tester: with replaceable high sensitivity probe, easy to use, automatic pH calibration, two sets of calibration points are optional 4. Multifunctional meter with automatic temperature compensation: temperature can affect reading levels, the digital pH tester has an even better range of 0.0°C-60.0°C (32.0°F-140.0°F), automatic temperature compensation can