The Philips HeartStart FRx Defibrillator (Recertified) is designed to be easy to use, rugged, and reliable for those who get there first. On the scene with law enforcement, on the field with student athletes or on the job with employees, the FRx Defibrillator is the solution for treating Sudden Cardiac Arrest (SCA) from ventricular fibrillation in environments and conditions too demanding for many other defibrillators. Reliability backed by Philips. The HeartStart FRx Defibrillator is powered by an easy to install, long-life (four-year) battery, so you know the device is charged and ready. The device's automated daily, weekly and monthly self-tests check the pads readiness, and verify functionality and calibration of circuits and systems. With over 85 tests, the FRx is one of the most comprehensive self-testing devices on the market and is virtually maintenance-free. The blinking green "Ready" light on the defibrillator is your assurance that the device is ready for use.