4mm, 5mm, and 6mm hex set, Park Tool introduced the bicycle industry to the 3-way Hex Wrench Set more than 20 years ago. Our latest versions are stronger and more comfortable than ever. They fit perfectly in the palm of the hand and provide tremendous leverage. Hexes are made from Bondhus Protanium™ high torque industrial steel and are heattreated for long life. Tips of hexes are chamfered for a perfect fit, The AWS-1 now features color coded rings to speed finding the correct size. Blue- 4mm. Black- 5mm. Gray-6mm.