For nearly 70 years, NORMA Group pioneered the development of hose clamps and perfected the worm drive hose clamps (WDHC). We remain one of the world's foremost innovators, producers and suppliers to the heavy equipment, construction and agriculture industries. Our portfolio of WDHC's include constant-tension hose clamps that offers a wide range of diameters, screw types, housings and materials to satisfy the needs and requirements of your applications.