For Associated B6D with StandUp gearbox. Allows to move your battery closer to the motor. The battery will sit 7mm further back. Still able to move it forward.
You will have to modify the side rails with a Dremel (remove 7mm. of plastic), see the pictures.
There are three parts: One central brace and two side battery stops, cut them apart with a hobby knife.
Great to gain rear grip on low grip / outdoor / dusty tracks.