This is the optional Adjustable Aluminum Motor Mount for the Traxxas 4-Tec 2.0FEATURES: Replaces stock plastic mount allow a much wider range of Gear Ratio. Improves power transfer for non-stock gear ratio use. It allows users to obtain better gear mash . CNC Aluminum motor mount can also dissipate heat and cool down the motor. YOU WILL RECEIVE: One-Adjustable Aluminum Motor Mount One-Pivot collarsTwo-Motor mount screwCOMMENTS: This will allow better gear mesh for non-stranded gear ratio. Replaces Traxxas TRA8390For easy stock gear ratio set up, consider Hot-Racing TRF1801 as an alternative.