The Smart Pads II are a multi-function unit designed for use with the Philips HeartStart FRx AED. These pads are suitable for use on adults, children and infants, so rescuers don’t need to worry about changing the pads for younger patients. They also sense when they have been removed from the cartridge and applied to the patient, letting the AED know at what point the rescuer is in the resuscitation process. To use the Smart Pads on infants and children, simply insert the Infant/Child Key into your HeartStart FRx AED Defibrillator. Key must be purchased separately. These pads are packaged in a semi-rigid case for added protection, ensuring they are always ready to save lives. It’s recommended to check the status and expiration date of your battery pack when purchasing these pads. Smart Pads II are single-use only with a 2-year shelf life.