WATERPROOF ORP METER SPECIFICATION:  Measuring range: -1200~ 1200mv  Measurement accuracy : ±2mv  Resolution : 1mv Calibration: automatic calibration within 7 seconds  Temperature accuracy (TEMP): ±0.5 °C  Resolution (TEMP): 0.1 ° C  Temperature compensation range: automatic temperature compensation (ATC)  Power supply mode: 3 * 1.5V (LR44)(not included)  Power supply voltage : 4.5V  Product size: 187*37*37mm  Standby: automatic calibration after 10 minutes  Product weight: 80g Lock: hand button lock ORIGIN : GABY INSTRUMENTS