Why the 14-inch 31020 leads this service shortlist
The 31020 gives this guide a conventional reference point: a 14-inch straight wrench with a ductile-iron body and replaceable gripping jaws. Its place is on suitable threaded round pipe, not on every fitting that happens to be in a plumbing system. For a buyer assembling a first service kit, the useful comparison is whether this length fits the work and whether its weight is acceptable alongside cutters, pliers and diagnostic tools.
When the smaller or aluminum alternatives make more sense
The 12-inch 31015 is the more compact sibling; the 18-inch 31100 changes both reach and body material. Neither is simply an upgrade to the 31020. If you work inside cabinets, a shorter tool may earn its place more often than a longer handle. If the wrench travels upstairs on every call, compare aluminum alternatives at the same size before buying the largest option. Manufacturer dimensions establish those differences; they do not establish a measured comfort advantage.
What to inspect before ordering
Confirm catalog number 31020 rather than relying on a photograph shared by the whole wrench family. Check the jaws, adjustment assembly and replacement-part support in the manufacturer documentation. Decide how the workpiece will be counterheld and whether the finish permits serrated contact. A matching second wrench or a smooth-jaw tool may solve the actual problem more usefully than one oversized wrench.