The main difference between the W3 constant tension worm-drive and the standard Mikalor worm-drive is to be found in the inner-ring insert incorporating a spring. This spring-loaded insert maintains constant pressure around the hose in case of sudden variations in temperature and /or vibration thereby avoiding leaks. The fact that this clamp guarantees leak-proof hose assemblies with both gaseous fluid and liquids makes it ideal for applications in car, tractor or heavy machinery engines. Moreover, the nonperforated cold formed band together with the rounded band edges make sure that no damage occurs to the hose. This clip complies fully with the DIN 3017 norm and also with the RoHs directive EU/2002/95/EC dated 1st July 2006.