Extech RE300 ORP Meter

Portable, waterproof measuring device features a large display with bar graph, 15-reading memory with recall and easily replaceable electrode module. Rubberized, no-slip-grip housing floats in water. Waterproof ORP Meter comes complete with electrode, protective sensor cap, sample cup, four LR44 button batteries and neck strap. Features an automatic electronic self-calibration and a simulated analog bar graph displaying any change in the ORP reading.