Durable: These hose clamps are made of high quality 304 stainless steel, rustproof and long service life. Smooth Surface: The surfaces are well polished and the edges are also smooth, so they will not scratch or damage the pipes. Size: 18-20 mm. Easy Installation: Convenient to install or remove by using either a flathead screwdriver or a hex wrench. Application: Suitable for thin-walled pipes in small sizes such as air pipes, water pipes, fuel pipes, silicone hoses, etc.