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 which firmly retains each key in a size marked hole Sizes include: .050", 1/16", 5/34", 3/32", 7/64", 1/8", 9/64", 5/32", 3/16", 7/32", 1/4", 5/16" and 3/8". Color coded red for inch. Made in the U.S.A.