Some roof boxes, particularly older boxes, come with U-bolts that are not wide enough to fit around modern wing-shaped roof bars. Alternative roof bar fittings are often available that will allow you to use your roof box on you new roof bars. Usually these alternative fittings will be T-bolt fittings that slide into the channel on aluminium bars. This provides a very neat and secure fitting that won't risk scratching your roof bars.
If you have an older box and would like us to check if we have any alternative fittings please contact us. We will need to know the make and model of your roof box and also see a photo of the box and the fittings inside the box. We would also need to know what type of roof bars you have (or plan to purchase).