Material: Durable 304 stainless steel. Compatible with normal stainless steel, it is safer, more durable, non-toxic and corrosion-resistant. It is of high hardness and not easy to deform. Suitable for pipe diameter 52-55mm Package: 4PCS The unique locknut design locks the hoses or pipes under vibration and torque. Please measure the outer diameter of the pipe you are installing before purchasing.