Winterize Sprinkler Systems with Air Compressor to National Pipe Threads (NPT) Set Blow Out Adapter - Contains all common sizes! Adaptor to winterize underground irrigation sprinkler systems Includes most common pipe thread combinations! Avoid multiple trips to the hardware stores. Pressure rating: 250 psi with 4:1 safety factor. 100% outdoor rated, virtually indestructible, impervious to water and oil All metal parts are brass. Hose is 3/8" ID Goodyear Insta-Grip, made in USA. Assembled in USA.