the job done now ! . - industrial Strength Magnets for fantabulous bit retention - Constructed of Impact Grade Cr Vanadium Steel with a Manganese Phosphate coating to help to prevent rust and corrosion - 1/4 '' hex stem that fits any classical drill chuck - These 6 '' longish impact drivers thoroughgoing with a storage rail so you 'll never lose one on the job ! . Includes - 1/4 '', 5/16 '', 3/8 '', 7/16 '', 1/2 '' and 9/16 '' sizes .