Treat cardiac arrest patients with your Philips HeartStart FRx AED no matter their age. The Philips HeartStart Infant/Child Key is used only with the FRx Defibrillator when treating an infant or child less than 55 pounds or 8 years of age. Simply insert the Infant/Child Key into the FRx and the AED will automatically reduce the defibrillation energy and provide voice and CPR coaching specifically geared for treatment of infants/children. The pads icons also flash to show you the appropriate pads placement.