High quality, industrial grade professional set. Made with Eklind Alloy Steel. Heat treated for optimum strength and ductility. Finished with Eklind Black Finish to resist rust. Plastic holder firmly retains each key in a size marked hole Size include: 1.5mm, 2.0mm, 2.5mm, 3.0mm, 4.0mm, 5.0mm, 6.0mm, 8.0mm and 10.0mm. Color coded Blue for metric. Made in the U.S.A.