size: 1, 2, 2.5, 3, 4, 5, 6, 8, 10mm

A tool commonly used to tighten and loosen screws or bolts with an internal hexagonal socket, which also called Allen wrench.

There are two most shapes, L-Shaped and T-Shaped, hex wrenches are commonly found in L-shaped and T-shaped designs. 

The L-shaped Allen wrench is the most common, featuring a long and short arm, making it versatile for different angles.