A good set of allen wrenches is a must have for any homeowner, or shade tree mechanic. Basically, an allen wrench is a metal rod, sometime ell shaped, or sometime tee shaped. The metal rod is eight sided, like an octogon. They can be made from several different metal alloys, depending on the quality of the kit purchased. A good set generally contains SAE sizes 1/16 through 1/2 inch. It's a good .