BrassCraft compression adaptor 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. | BrassCraft Speedi Plumb 3/8 in. O. D Tube 1/2 in. D FIP Chrome Plated Brass Adapter - 4839791 | Ace Hardware