Gearbox sprocket 19 Tooth, Norton AJS Matchless AMC gearbox and Norton laydown gearbox, 5/8in x 1/4in. Suits models Norton singles and twins from 1957. Can be used for Norton laydown gearbox with addition of the spacer part 040131E. Original part number: 040010/19 - Axle sprocket (should fit E12/368 Norton laydown gearbox)