Inside virtually every ready-to-assemble product requiring screws is a complementary Allen wrench, a compact hexagonal tool that can quickly twist and secure fasteners for bookshelves, tables ...

Even if you’ve never bought an Allen wrench, chances are you probably have one or two lying around the house. These are the small L-shaped hand tools that come free with most flat-pack furniture ...

You can grab a monkey wrench. Want to put together an IKEA bookshelf? An Allen wrench works. If you have a plumbing issue, however, you’re likely to turn to the wrench that can sink its literal ...