Extech PH300 Waterproof pH meter mV and Temperature Kit

Amazon

Measures pH, mV and temperature at your workbench or in the field Automatic calibration (4, 7 and 10pH) Choice of three point calibration for better accuracy Automatic temperature compensation Memory stores up to 200 readings with series number, measured value and temperature

Test-meter.co.uk

Waterproof 3-in-1 pH metre with automatic calibration, temperature compensation, 200-reading memory. IP67 rated, large backlit LCD. Ideal for lab and field testing with ammonia and purified water modes.