Commonly cars are fitted with a twelve volt battery. It provides the electrical power to start the engine and power all the electrical systems on the vehicle when the engine is not running the alternator. The battery is connected via two terminal leads which are found adjacent to the battery compartment. This can be under the bonnet in the engine compartment, under the rear passenger seats or in the boot compartment.

The battery is connected with two leads which have terminal connectors. There is one positive connector and one negative. The connection points on the battery are two round lead posts at either end of the battery. The terminals on the ends of the leads are made of a zinc alloy and are a circular clamp type of construction.which slip over the lead posts and have a nut and bolt that squeezes the clamp tight. The lead slots into a tube on the side of the clamp and is held in place with two retaining screws. Some modern terminals have a quick release mechanism incorporated and some also have a insulated cover/cap.

Problems that occur with terminals are concerning a good electrical connection. Corrosion, oxidation and metal fatigue may lead a necessity to replace. battery terminals screw on is the ideal replacement part, specifically manufactured for the make and model of your vehicle. Normally the terminals are supplied in pairs and marked positive + and negative -