A hose clamp or hose clip or hose lock is a device used to attach and seal a hose onto a fitting such as a barb or nipple. Screw clamps consist of a band, often galvanized or stainless steel, into which a screw thread pattern has been cut or pressed. One end of the band contains a captive screw. The clamp is put around the hose or tube to be connected, with the loose end being fed into a narrow space between the band and the captive screw. When the screw is turned, it acts as a worm drive pulling the threads of the band, causing the band to tighten around the hose (or when screwed the opposite direction, to loosen).