Material Color: Material: made of high qualityAluminum. Color: Black Specification: 1.100% quality assurance tested, more responsive, less expensive, easier to install. 2.AN flare caps block off fuel hose line,prevent dirt and debris from entering adapters. 3.Anodized for great appearance,anti-corrosion durability, long last and strength. 4.Designed for leak proof sealing with any manufacturers adaptor fittings. 5.Completely reusable, just disassemble and put onto another hose. 6.Precision-machined to exact tolerances for trouble-free performance. 7.Max Pressure: 4000psi (275bar). 8.Working Temp Range: -65F to +252F( -53to +122). About Block Off Nut: The AN thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It became popular for usage within Professional racing for the ability to easily customize new lines. From there it s usage spread to the aftermarket automotive performance field for its ease in adaptability, upgradability and durability. InstallationSteps: Hexagonal shape is easy to install. Screw in by hand and tighten it with a wrench. Adjustable wrench is recommended Package Included: 1pcs xFlare Cap Tube Fitting.(100% Brand New Never Used Or Installed)