A tool by many names, this hex wrench set (AKA hex key or Allen wrench/key set) probably looks familiar if you ve ever purchased prefab furniture. These small but mighty tools are great to have around in all of their many sizes for lots of reasons. In addition to furniture assembly, they can tackle bike maintenance, electronics, and automotive needs, and are go-tos for super tight spaces that require manipulating a hexagonal bolt (that s six sides, if you re counting). This set comes in both SAE fractional inch and metric sizes - it s essential to have them all as they are each designed to fit perfectly in a single size hex bolt. All Character tools are made in professional-grade factories and warrantied for life.