The VEX Crystal Upgrade Kits allow you to change the frequency used by the transmitter controlling the VEX autonomous robot. The transmitter included in the Dual Control Starter Bundle uses a standard frequency for all kits. In situations where you want to control two or more robots simultaneously using multiple transmitters, such as during a competition, it is necessary to change the frequency used by the transmitters so that each robot is controlled by a transmitter with it's own unique frequency.