BrassCraft compression nut is machined from brass. Compression fittings are ideal for use in plumbing, instrumentation, hydraulic and pneumatic systems (gasoline, grease, oil, potable and non-potable water, vacuum and air lines). Can be used to install copper, aluminum, or plastic tubing. Not recommended for use with steel tubing. Brass construction provides strength, durability and longer-lasting performance Designed for use with aluminum and copper tubing. Not recommended for steel tubing Not for use in potable water applications Little to no tube preparation required. Connection does not require flaring, soldering, or other types of tube preparation Plastic and PEX tubing installations require sleeves and/or inserts. Check installation instructions for exact requirements Rough Brass May be used in both indoors and outdoors. Temperature rating: -65° to 250° F at maximum operating pressures Working pressure: 200 psi