Brass Nut, 3/8

The Midland Metal Brass Nut in 3/8-inch is the compression nut that secures a 3/8-inch tube fitting, drawing the ferrule tight against the tubing to form a durable, leak-resistant seal. Made from sturdy brass, it delivers the corrosion resistance, thread strength, and mechanical durability expected of quality plumbing hardware for water treatment and supply-line work.

When threaded onto a fitting body and tightened, this nut compresses the sleeve, or ferrule, onto the tubing. That action locks the connection in place and seals it against leaks. The reliability of the whole joint hinges on using the correctly matched 3/8-inch nut, because proper thread engagement and uniform compression are what create a connection that stays tight under operating pressure rather than weeping or slowly working loose.

• Brand: Midland Metal Mfg
• Fitting type: compression nut
• Material: brass
• Size: 3/8 inch
• Works with matching ferrule and fitting body
• Item weight: 0.02 lbs

This 3/8-inch nut is a common assembly and replacement part for installers building or repairing tubing connections on filtration systems, reverse osmosis units, and accessory lines. Compression nuts can become cross-threaded, stripped, or lost during service, so keeping correct replacements available prevents a job from stalling over a single missing piece of hardware.

For a complete, dependable fitting, combine this nut with the correct sleeve and, when using soft tubing, a tube support insert that keeps the tube round under compression. During assembly, start the nut by hand to avoid cross-threading, then tighten to a firm, leak-free fit without over-torquing the brass threads. Affordable and frequently needed, brass compression nuts are a smart item to keep stocked, ready to support clean installations and quick, confident repairs whenever you work with 3/8-inch tubing. Because a stripped or cross-threaded nut can hold up an otherwise simple repair, keeping correct spares within reach is a small step that keeps both planned installs and emergency fixes on schedule. For RO units and multi-stage filters where many compression joints share a small space, keeping the correct nuts organized by size keeps the work clean and avoids the frustration of hunting for the right piece mid-assembly. A well-stocked, well-sorted fitting kit is one of the quiet keys to fast, leak-free tubing work.