A defibrillator is a critical medical device used to restore normal heart rhythm in individuals experiencing cardiac arrest or arrhythmias. It delivers an electric shock to the heart, stopping abnormal electrical activity and allowing the heart's natural pacemaker to resume control. Defibrillators can be found in various settings such as hospitals, ambulances, and public spaces like airports and gyms. They are user-friendly devices that provide clear instructions on-screen for rescuers to follow, including prompts for performing CPR if needed. Training in basic life support and defibrillator use is essential for individuals operating these devices to ensure timely intervention and maximize chances of survival. The availability of defibrillators in public areas has been shown to significantly improve outcomes for sudden cardiac arrest victims, highlighting their importance in emergency response efforts.