Confused? There is help. Sea Tech, Inc. (www.seatechinc.com) supplies PEX and fittings to about 85 percent of U.S. boat builders. With the year and make of your boat, a fairly accurate measurement of tube outside diameter and a good digital photo of one of the quick-connect fittings aboard, Sea Tech’s customer service department can determine what size fittings you’ve got and match it with one of their product lines.

Easier still, most tubing is marked with size, and a close look at the collet on most quick-connect fittings also indicates size. Or swing by the plumbing aisle of Home Depot and compare your tubing with PEX tubing and SharkBite (www.sharkbite.com) quick-connect fittings.