These are precision clamps made from #304 stainless steel designed to prevent the hose or tubing from contacting and being damaged by contacting the clamp's screw tightening mechanism. These clamps are size range specific therefore, it is important to carefully measure the outside diameter of the tube or hose before ordering clamps. For example if the clamp is 6-16mm it will make a good connection to a hose that is 8-14 mm diameter. In all cases we refer to the outside diameter of the hose and the inside diameter of the clamp.