If you're looking to hook up a pitcher rinser or sink faucet in a coffee cart, this is the piece you haven't been able to find at any hardware store, plumbing store, etc. It took me forever to realize that this was the one thing I was missing. If you're hooking up a Flojet (or similar), you'll bring the 1/4" tube to the 3/8" tube with another adapter piece, then the 3/8" tube to this so that it connects to the rinser/sink line. Don't hesitate - buy it now so you can finish your project sooner!