400E, 500E, E420, E500 : There are multiple tooth count options for this application. E3 gear has 48 teeth on the outside and then between 12 and 21 teeth on the underside gear, original gear is amber in color. (Must count teeth on original gear before ordering). {If you cannot count the teeth on the main gear then count the teeth of the next gear that it meshes with. If your tooth count is 39=48x21, 41=48x19, 42=48x18, 43=48x17, 44=48x16, 45=48x15, 46=48x14, 47=48x13, 48=48x12}