A hex key, also known as an Allen Key, Allen wrench or hex wrench is a small L shaped or T shaped tool with a 6-sided hexagonal tip which is used to loosen hex socket screws or bolts.

Types of Hex Key

L-Shaped Hex Keys: L Shaped Hex Keys or L Keys are the most common type of hex key with a hexagonal tip at each end

T-Shaped Hex Keys: T-shaped hex keys or T bar Allen Keys have a crossbar or T shaped handle at the end which provides a better grip

Folding Allen Key Sets: Folding Allen Key Sets consist of an outer casing from which a selection of different sized Allen keys can be unfolded, a bit like a penknife or multi-tool

Hex keys or Allen keys are available in metric sizes and imperial sizes Imperial Allen Keys. They are also available in Allen Key Sets which include a range of popular hex key sizes including 12mm Allen keys.