... for ORP Two switching contacts as set-point relays Automatic or manual temperature compensation WELLORE WL series PH/ORP monitor & Electrode ... ~14 PHResolution:1 mV 0.01 PHAccuracy:±1mV :±0.05PH Temperature compensation : automatic temperature ,from 0~60°C,reference Tem.25°C ... ,temperature compensation unit as NTC10KΩOutput:4~20mA,max load 1000Ω ...