The Powerheart G3 Automatic has a fully automatic operation. There is no "shock" button to be pressed, so the patient is not hindered by a confused or uncertain care provider. The AED gives a shock when it determines that it is necessary. Reliable, durable and easy to use. Every day the AED tests the battery, hardware, software and electrodes. Once something is wrong, the Rescue Ready status indicator in the handle signals that through light and audio signals. The AED uses both voice guidance as a display in which the instructions appear in text. Thus, the rescuer is guided through the process. Where there is too much noise to hear the voice, the display provides guidance. In addition, the AED also has a metronome on board that indicates the rate of chest compressions.