This is a battery holder conversion to change the battery mount- ing of MD1.0 to inline mounting.

When the car has a certain degree of grip, mounting the battery inline (in the front-back direction of the chassis) suppresses chassis roll, enabling sharper movement when transitioning to an acceleration position at the exit of a corner or when turning a corner. In addition, the front load is slightly increased, which allows the car to steer better during cornering and provides a high degree of control.