This is the entire housing connection that contains a pressure gauge, needle valve, return and outgoing tube connection fittings. It screws directly into your system pump.
See the 2nd picture in the product description that shows exactly what this replaces. See area circled in red.
This is 1/4" Tubing For Misting Systems. It fits all 1/4" fittings and spray nozzles.
Please be sure to choose either black or white below tubing below. There is absolutely no difference in the structure of each tubing, other than the color. We do however recommend black tubing if your application is in direct sunlight.