For much of the latter 20th century, household plumbing systems depended on copper pipe—a difficult-to-master building material whose price only rose along with the ever-increasing demand. Today, many pros and do-it-yourselfers prefer to use tubing made of cross-linked polyethylene,  In addition to being cheaper than copper。

PEX boasts the added advantage of being bendable. That means, compared to straight, rigid copper, PEX requires fewer connections and fittings, enabling installers to get the job done more quickly and with relative ease. Furthermore, once in place, tends to fare better over the long haul, because durable plastic resists the mineral buildup and corrosion to which copper often succumbs. Even better: PEX stands up admirably well to freezing temperatures, unlike metal pipes that freeze and in severe cases, burst open.

In other words, “for many plumbing applications, you can’t do any better than PEX,” says Daniel O’Brian, a technical specialist with leading online vendor Yet for all its advantages and despite its soaring popularity across the building and remodeling industry—PEX remains poorly understood by the average person. In part, that’s because cutting, crimping, and clamping the material requires specialty tools to which many are unfamiliar.

However, according to O’Brian, those who are new to PEX often get tripped up, not when installing the tubing, but rather when choosing which type to install. After all, PEX comes in more than 20 different varieties, each of which boasts its own set of pros and cons, and its own set of ideal applications. When shopping for PEX, therefore, “you must carefully consider the requirements of the project,” O’Brian explains, and from there, “decide which product would make the best match for the task at hand.”  To be successful, O’Brian concludes, “You need a basic understanding of the four main types.