Brass Push>Connect Metric Tube Fitting, 4.00 mm Tube OD Union

Push-to-connect fittings like this one use a collet ring and Buna-N O-ring seal that grip the tube mechanically once inserted. At 4mm tube OD with a max working pressure of 250 psi, the connection stays secure under normal compressed air and instrumentation line conditions. The brass body with nickel plating also helps resist the kind of corrosion that tends to cause joint failures over time. If you ever need to pull it apart, you just depress the collet ring with two fingers and the tube withdraws clean. Reusability is built into the design, so repeated connect and disconnect cycles won't compromise the seal integrity the way a crushed ferrule fitting would.

Push the tubing straight into the fitting and it locks in place, no tools needed. To disconnect, press the collet ring in with two fingers and pull the tube back out.

This union is designed for use with compressed pneumatic instrumentation circuit lubricant and cooling lines, and it's made from brass with a nickel plating for durability.