There are different socket heads to choose from including; Hex Sockets- there are two different types of hex sockets, six point and twelve point. The number of points that they have refers to how many angles are inside the socket head. The twelve point socket, however, also known as a double hex, will be more versatile with hexagonal bolts and is perfect for tight spaces. Impact Sockets- has an industrial, black, surface instead of a polished metal surface like other sockets. They are designed for power impact wrenches which uses more force and vibration in the removal of fasteners. Spark Plug Sockets- generally much longer than other sockets and they have a rubber insert to prevent electrocution. They were designed for the removal or fastening of spark plugs. Socket Bits- these are hex sockets that have a bit in their middle. They are able to work with impact drivers and a variety of manual tools. Universal Joint- designed to help with reaching a bolt head that is in a tight space or when something is in the way. It has a ball swivel allowing it to turn a complete 360 degrees.