Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications. There are two type of ball valves based on the ball type, floating ball valves and trunnion mounted ball valves. Depending on the bore size of the ball itself, ball valves are designated as full port ball valves and reduced port ball valves. A full port or more commonly known full bore ball valve has an over-sized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted but the valve is larger and more expensive so this is only used where free flow is required, for example in pipelines which require pigging.