Fully automatic defibrillator that assists the operator with the correct execution of cardiac massage during the cardiopulmonary resuscitation, due to the external CPR-quality sensor. Reliable and durable (1m drop test: dustproof and waterproof resistance IP rating of 56), making it capable of tackling challenges in various severe environments. CPR-quality feedback device is designed to optimise the delivery of the CPR by providing simple and accurate responses to the rescuer in real time. Checks for a shockable rhythm and, if detected, will warn the user of the imminent shock delivery. After 5 seconds, the defibrillating shock will be released automatically. Following the defibrillation, cardiopulmonary resuscitation will be guided by voice prompts and the metronome which marks the various cycles of compressions and insufflations.