On the wheel side it says 29500-201-016, on the other gear is just "Veglia"
Sizes are ø outside 50mm, the gear side, 51mm the flat side with a small recession in the middle
ø 47 mm inside
height 21 mm
I checked with the castwheel GT and they are interchangeable.
I have another one stamped 29500-201-019 Veglia (only the wheel side), don't know where that one is from but the measurements are the same.
it is for a drum 350 brake sport ,
i have the wheel ,and the external gear, but not the gear fitted to the hub.
i'll check this weekend if it measures up.