Philips OEM FRx/OnSite/HS1 AED Replacement 4-Year Battery
4 year warranty and 5 year shelf life
Typically last 4 years installed in the device for a "ready to use" condition while running vital self tests 
Manufacturer recommends a backup battery to be stored with the device 
The Philips HeartStart M5070A defibrillator battery has the capacity to deliver a minimum of 200 shocks or 4 hours of patient monitoring