Controllers - drivers for e-bikes. Controllers are part of each Rapid Kit. The C1100 controller is built into the battery rail, the C2100 controller is placed in a case fastened to the bicycle frame.
The more powerful the driver -the more power we get from the e-bike.
For C3000 controllers you need a larger - more capacious - battery (over 20Ah) or a battery built on high-current cells.