Assortment contains 6-piece each of: 3/16 in, 1/4 in, 5/16 in and 3/8 in and 4-piece each of: 7/16 in and 1/2 in. High quality steel material. Zinc plated finish. Sizes are clearly marked on each piece. Precision Brand® keystock is used to provide driving torque between shafts and pulleys, gears, sprockets, etc. Used for new machinery, general maintenance and shop repairs. It is a necessity in all applications where rotating power devices are used. Most tolerances on dimensions are oversized to assure tight fits in keyways for positive, zero backlash power transmission.