These components, commonly employed in plumbing and gas conveyance, refer to iron-based connectors and segments finished with a protective dark coating. Their dimensions are specified numerically, designating the internal diameter in inches for compatibility with corresponding pipes. These parts are typically joined using threaded connections to create secure and leak-resistant pathways for fluids or gases.
Their prevalence arises from a combination of durability, cost-effectiveness, and resistance to high temperatures and pressures. Historically, these have been a staple in industrial and residential applications due to their robust construction and ease of installation. The dark finish offers a degree of corrosion protection, extending their lifespan in demanding environments.