AED - Defibtech Lifeline 5yrDefibtech Lifeline Semi AED (Semi Automatic). The original award winning Defibtech AED, the Lifeline Semi Automatic is easy to use with only 2 buttons and the only 5 year battery available in the world. It also comes standard with an 8 year Warranty. Easy to use with simple, clear and straightforward instructions. There are only two buttons on the unit, a green button to turn the unit on and a red one to shock the patient, if needed. The Lifeline AED