1Universal Application: The kit includes a red and black connector for connecting the positive cable to the earth cable. Thru panel battery connector is suitable for a variety of applications from car audio to marine. 2Main Function: 3/8 inch nickel plated copper terminals allow you to properly secure cables as large as 4/0AWG to your firewall with sufficient torque to pass current to the other side. 3Safe and Easy Use: Battery terminal, is used to easily connect power and ground, provides firm attachment points for installation. 4Premium Material: Thru panel battery terminal connectors are made of high grade nickel plated copper materials to ensure stable performance and long durability. 5Strictly Tested: Thru panel battery terminal has been extensively tested, safe and dependable, will last in the car for a long time.