STZ cut pipe is composed of durable, schedule 40 black steel and is hydrostatically tested and available to fit residential and light commercial gas and air applications. This has protective durable plastic end caps that help ensure the pipe threads remain undamaged in transport. Not for use with drinking water. Always check your local plumbing and gas codes before starting any piping projects. Hydrostatically tested, steel construction, Made to ASTM A53 specifications.