This Zinc-Plated Carbon Steel flare x female adapter gas fitting is economical, reusable and resistant to mechanical pullout and can be used with copper, Zinc-Plated Carbon Steel, aluminum and welded steel hydraulic tubing that can be flared. Not recommended for polybutylene or soft plastic tubing. Commonly used for gasoline, grease, oil, water, vacuum, air lines, LP (liquefied petroleum gas) and natural gas.