The Jenco Model 3671 pHORP Controller is an all solid state for measurement and control. This controller has two output relays for onoff control. The controller has a programmable highlow alarm relay. Specifications:Units: 6Power: 115VAC, 230VAC 15, 5060HzResolution: 0.1 pH, 10 mV, 1CRange: 0 to 14.0 pH, -1990 to 1990 mV, 0 to 100CAccuracy 1: 0.1 (relative), 1C, 0.1 mVTemperature compensation: auto 0 100CRelay output: 8A at 115VAC, 4A at 230VACReadout: 0.56 in. high efficiency red LED displayWeight (each): 0.