Ideal for high pressure applications up to 5,000 PSI Suitable for a wide range of industrial and HD applications Black oxide coated for superior protection against rust and corrosion Uniquely designed compression sleeve provides a seal tight connection 1 fitting per bag ...Ideal for high pressure applications up to 5,000 PSI Suitable for a wide range of industrial and HD applications Black oxide coated for superior protection against rust and corrosion Uniquely designed compression sleeve provides a seal tight connection 1 fitting per bag 4LifetimeLines High Pressure Compression Unions are ideal for high pressure applications where a regular compression fitting just won't do the trick. Black oxide coated for superior protection against rust and corrosion, these compression fittings create a leak proof seal. Compression fittings are extremely useful due to their extreme temperature and pressure capabilites, rating up to 5000 PSI.