Roof Boxes G3 Or Junior Available here. Roof boxes attach to the roof of your car and provide an external storage solution for big and bulky items which are normally difficult to fit in the car, things like luggage, prams, camping equipment, sports equipment and other large cargo. A roof box allows you to free up interior car and boot space so that you can enjoy a more comfortable journey, or even take more things with you on your travels. Loved by families going on driving holidays, a roof box is vital because it allows you to maximise space in the car and still fit in everything you need for your holiday. Roof boxes attach to a set of roof bars mounted on the roof of your car. They are designed to be aerodynamic, meaning that they will provide a minimal amount of wind noise while driving. Explore the new Thule roof box on MicksGarage.com today and save.