Specification: No need to reset the time and date within 10 minutes of battery replacement Built-in rechargeable circuitry allows the use of rechargeable batteries. Test Method:Oscillometric Test Range:Pressure 40-20mmHg Pulse 40-180 beats/min Measurement Accuracy:Static Pressure:St 3mmHg Pulse Count:Within 5% of cab of readout Storage Environment:Temperature -20C-55°CC Relative Humidity less than 85%Product Dimensions:78(W)x75(D)*28(H)mmWeight:Approx. 107g (without batteries)Power Supply. 1.5VAAAA size batteries two