ZK-052 Car Anti Zap Protector 12V/24 Prevent Damage Electrical System, ZK-0521. Prevent damage to the electrical system when welding sheet metal pulses. 2. It can protect the electronic equipment of the vehicle when welding or jumping start. 3. Suitable for 12V 24V system. 4. Polarity protection reverse connection warning. 5. Designed to be installed across battery terminals to absorb unnecessary surges. 6. LED indicator light: green light on = protection; red light on = no protection. In the absence of protection, an alarm