The Physio-Control Lifepak 9 is a defibrillator/monitor with a microprocessor. The Lifepak 9 defibration system offers a simple, user-friendly operation. The Lifepak defibrillation system features both high and low energy selections, cardioscope, non-invasive pacing, and 3-lead and 5-lead ECG monitoring. The Physio-Control Lifepak 9 also features an adaptor that allows for hands-free defibrillation. The microprocessor determines how many joules of energy are required for defibrillating a patient. Allowing the system to readjust to low battery power or lower voltage uses, with paddles for both adult and pediatric patients.