These are self-sealing, no pipe dope or Teflon tape required.
All of our fittings accept 1/4 inch, 3/8 inch, or 1/2 inch (outer diameter) airline (tubing). The airline simply pushes into the push-on fittings and allows the hose to swivel.
Determining Thread and Airline Sizes
How to use Quick-Connect Push-On Fittings