HeartSine has taken an innovative approach to AED maintenance by incorporating the electrodes and batteries into one single-use cartridge called the PAD-PAK. The advantage to the PAD-PAK is that there is only one date to monitor and only one item to replace upon expiration or after use. This HeartSine Samaritan Adult PAD-PAK TSO-C142a is certified for Aviation. The PAD-PAK is suitable for use on adults and children over 8 years and weighing more than 55 lbs.Read Less-