This is the newer version of TAMIYA (#53620) aluminum propeller shaft for TT01. The new shaft is slimmer than the (#53620) and comes with front and rear aluminum propeller joint cups. This is my very first upgrade for my TT-01D. I need to disassemble down to the chassis tub to upgrade it but it is very well worth. My TT-01D has improved in acceleration and deceleration response after this upgrade. I recommend you buy this upgrade along with your new TT-01/D/type E so that you can build the chassis right away with the new upgrade Tamiya (#54026) TT-01 Alu.Prop.Joint Shaft. Furthermore, this is the best selling TT-01 hop-up option parts and it always run out of stock very fast even at any hobby RC shop.