The Autel OBDII Memory Saver, is a polarity-protected cable that attaches to a 12 Volt backup battery to provide power via the OBDII/EOBD port to onboard electronics while the vehicle's battery is disconnected, preventing vehicle data loss and saving the time and effort of re-coding systems. Features surge protection and three LEDs to indicate power supply status. Preserves vehicle codes and electronic presets when replacing the battery Enables the vehicle's computer to be powered and maintain data when connected to vehicle's backup battery Connects to the vehicle via OBDII and the 12 volt battery with alligator clips Features surge protection and LED status lights One-Year Limited Warranty autel battery tester memory saver car monitor 12v obd2 automotive replacement auto volt tool for mercedes benz.