As of May 1, 2018, Japan produced vehicles use 17 mm hex lug nuts instead of 21 mm on the same size thread. When installing new lug nuts or the accessory Wheel Lock Set, make sure to use the appropriate part number for the vehicle you are working on. NOTE: The Mazda3 produced in Mexico is not affected.Use the GEPC or the Mazda Accessory web site [MXConnect (dealers.mazdausa.com)] to look up the correct part number for the vehicle you are working on.