Paediatric PAD-Pak is preferable if AED is being used on a child under 8 years of age or under 25kg. The unique battery and pad in one cartridge have a 4 year life or one use . The cartridge clips in and out of the Samaritan defibrillator quickly and with ease. HeartSine also offer free replacement of PAD PAK's after bona fide use, conditions apply.