... /ORP-8150 is a single/double channels pH/ORP meter, the pH/ORP value of channel 1 or 2 ... group can be select. pH/ORP8156Double channels: measuring pH and ORP.1 pieces pH electrode and 1 piece ORP ... ORP: -1999mV~+1999mVTemperature: 0~99.9Resolution: pH: 0.01pH, mV: 1mV, T: 0.1;Accuracy: pH: ±0.1pH, mV: ±0.5mV ... 0~99.9; Automatic three point calibration function;Standard pH solution: 4.01, 6.86, 9.18;Input ...