Many parents occasionally wish for a bit more quiet. For them, BIG offers the BIG-Whisper-Wheels wheel set as an upgrade for the BIG-Bobby-Car-Classic. Thanks to the special rubber compound, the little red racer rolls significantly quieter through gardens and children's rooms. The wheel set can be attached to all BIG-Bobby-Car-Classics using the included mounting tool. To do this, the cap clips of the mounted wheels need to be removed. The package includes fastening clips as well as an assembly instruction manual.