Includes, in addition to the brake drum support plate, the drive for the speedometer pinion.
If this axle is replaced with the one of the 10 inch models (Rally/Sprint), the fork can be converted to 10 inch by using the correct brake drum, dust cover and 10 inch brake pads.
However, the fork length of the 8 inch models is shorter than that of the 10 inch models.
Therefore, make sure that the 10 inch tire does not come to the fork during compression.