Oetiker 15500012 Stainless Steel Hose Clamp with Mechanical Interlock, One Ear, Clamp ID Range 18.2 mm (Closed) - 21 mm (Open) (Pack of 100) Clamp ear is dimpled for increased clamp force Visible deformation of ear for evidence of proper closure Mechanical interlock for secure closure and better corrosion resistance than a spot-weld Stainless steel for resisting scaling and corrosion