Philips FRx Infant/Child Key***This unique Infant Child Key is used only with the FRx defibrillator*** This is the secret that makes the Philips HeartStart FRx AED so cost effective to own. Other AEDs use pediatric electrode pads for use on children. It means you'll have to regularly replace them just like adult electrodes pads. The FRx uses a "key" that when inserted into the device, converts the FRx into a pediatric defibrillator. It is intended for use on children up to 8