A single Intellisense® battery is all that is needed to power your St John G5 defibrillator. This dependable, medical grade battery is tested rigorously at Zoll and then tested each day it is installed in your St John G5 defibrillator for presence and functionality to ensure readiness. Using patented Rescue Ready® technology and embedded circuitry, your Intellisense battery communicates performance condition, age, storage temperature, and other vital information directly to your St John G5 defibrillator. Once Intellisense supplies are installed in your St John G5 defibrillator, years of unmatched performance are delivered. In fact, each Intellisense AED battery comes with a 4-year performance guarantee.