Tamiya 15187 - L.W.Special Ratio Gearing 田宮迷你四驅車迷你四驅車後備配件齒輪 雙星孖星  [15187]

They're re-releases of popular Grade Up Option Parts.

Useable Chassis the above gear sets.

15053: Kind 3 Chassis.

15132: Type 5, Zero, and Super 1 Chassis. Gear ratio can be changed to 3.5:1(Kit is scheduled at 4:1)

15187: Super FM and Super TZ Chassis.