... back light 3.Temperature compensation 4. Anjun ph indicator controller with High QualityApplicationIndustrial waste water,pure water, circulating water,food ... pharmaceutical, etcFeatures:1.High impedance preamplifier, strong ability of anti-interference 2.Transmission distance between the indicator with electrode is 100m3 ... 96*96*125mm13.N.W: 1 KG Anjun ph indicator controller with High Quality