Field Link Portable Programmer allows you to modify the most commonly used settings in your Castle controller at the touch of a single button. Field Link for Driving settings: Cutoff voltage Auto LiPo cutoff volts per cell (3.0, 3.1, 3.2, 3.4, 3.5) Drag brake Brake strength Punch control Reverse type Motor type Motor timing and C. H. E. A. T. mode* *C. H. E. A. T. mode is a feature of the Mamba Max Pro and Mamba X ESCs only. This package includes one Field Link portable programmer specifically made to work with Castle surface controllers, and a USB cable.