This coupler has excellent durability, environmental properties, and versatility. Air tools, factory air piping, etc. The abundant body material, size, and mounting shape make it suitable for a wide range of applications. The key components made of steel have been heat treated to improve strength. Made of steel for air, brass and stainless steel for water. Opposite Hose Size: 3/4 inch / Hose Mounting Socket / Caution 1: Cannot be used for vacuum use when using alone or when connected. This is a product for business contractors.