Compression fittings are used extensively in Hydraulic, Gas and for hot and cold water systems to enable the connection of tube (copper, steel Nylon etc) to threaded components eg valves and tools; compression fittings are suited to a variety of applications, commonly in water plumbing systems such as where confined spaces where copper pipe would be difficult to solder without creating a fire hazard, and extensively in hydraulic industrial applications a major benefit being that the fittings allow easy disconnection and reconnection.