Pipe and tube fittings are components used for connecting, terminating, controlling flow, and changing the direction of piping in many different industries. Compression fittings do not require tools or sealants, and are useful in installations where a heat source, such as a soldering torch, is prohibited. When purchasing fittings, consider the application, as this will affect material type, shape, size, and required durability. Fittings are available threaded or unthreaded, in many shapes, styles, sizes, and schedules (pipe wall thickness).