Long flexible corrugated cryotransferlines are widely used at JET for the supply of liquid nitrogen and liquid and supercritical helium. Their low thermal losses allow to use a central distribution system with individual lines to each user with line lengths of up to 90m. The easy installation of the fully tested cryolines, their flexibility, high pressure stability and compatibilty with the remote handling requirements of JET were important design specifications. Some of the cryolines have been in operation for over 15 years and the paper reports about their excellent reliability records and the main performance data.