Pipe joints are an important part of plumbing systems. They are used to connect two pipes together and can be made from a variety of materials. The two most common types of pipe joints are ELLS and tees. ELLS are L-shaped fittings that are used to change the direction of a pipe, while tees are T-shaped fittings that are used to join two pipes together in a straight line. Both ELLS and tees are essential components of any plumbing system.