WirthCo 20099 Battery Doctor 3-in-1 Surge Protector and Charge Monitor Protects and displays the condition of your battery with the push of a button Protects engine computer and 12 Volt accessories from damaging surges when jump starting or recharging Protects and displays the condition of your charging system with the push of a button Includes two 20 inch wire leads with 3/8 inch diameter ring terminals Fits all 12 Volt batteries