An Allen wrench, AKA an Allen key or hex key, is a small hand tool used to fasten screws or bolts with a hexagonal socket. Either end usually works, although some sets only have one end.

EASY TO PICK: Supplied in composite case for safe storage and quick key selection. Each wrench for quick size selection and easy organizing.

They're so named because you need an Allen wrench (aka an Allen key or hex key) with a hexagonal socket to tighten them. The hexagonal shape provides six points to apply pressure to the fasteners ...