One of the most important upgrade for your tamiya tt-01 chassis car. the main draft shift for every tamiya shaft drive gives equally the power to both front and rear gear diferentials and so on gives the power to the four wheels concomitent. The stock one is made by plastic with medal edges and it doesnt fits 100% giving to your car less than maximum speed. This aluminium shaft, that comes in red and blue decreases the friction and gives maximum power to all four wheels. before placing this item make sure to grease is well. Excellent product.