The Rolls-Royce Trent family comprises three-shaft turbofan engines developed for widebody airliners. Separate low-, intermediate- and high-pressure rotating assemblies let the architecture scale to different aircraft requirements. The Trent 700 began the family's airline service on the Airbus A330 in 1995; later branches include the Trent 800, 500, 900, 1000, XWB and 7000. Rolls-Royce also transfers matured technology back into earlier Trent engines through in-service upgrades.