Tamiya #50356 20T,21T, AV Pinion Gear Set
They are 48 pitch metric 20 tooth and 21 tooth gears. The number of teeth is stamped on the pinion so they cannot be confused which is which. They are made of aluminum.
Includes:
One 20T pinion gear (48 Pitch)
One 21T pinion gear (48 Pitch)
Two Grub Screws