Heartstart FRX/HS1 M5070A 9V 4.2Ah Li-MnO2SpecificationBattery Type: Lithium Manganese Dioxide (Li-MnO2) Voltage: 9V Capacity: 4.2Ah P/N: M5070A Fit Model: Heartstart FRX AED/HS1 Manuf: Philips