#C-Link Castle Creations USB Programming Kit. You only need one to control virtually any product Castle Creations makes. Castle Link contains a proprietary interface adapter and standard USB cable. All you need is an available USB port on your PC. Setting up speed controls, BEC's, etc. is very easy. The software drivers are upgradeable with all-in-one support.
The #CC-BEC Battery Eliminator Circuit is a little device that eliminates the need for a receiver and servo battery pack. It draws the higher voltage from the motor batteries and drops it to a pre-settable voltage level that is suitable for your receiver and servos. This is required in applications which draw high power for multiple servos or use more than 3S motor packs, as most ESCs with linear BECs are not designed for these applications. This device is programmable for different power settings with use of the Castle Creations Castle Link USB Programming Kit available under "Castle Accessories."