We have 3 types of Roof Box fittings to attach to roof bars which are shown below;

Clamps (top 3), U Bolt (Bottom left) & Thule Easy Snap U Bolt system.

The Top clamp is used on our Hapro Traxer box which can fit bars up to 95mm wide

The Middle clamps are used on all of our Thule, Exodus & Halfords Advanced boxes which can fit bars up to 80mm wide

The clamps on our Thule Force XT and Motion XT Boxes can fit bars up to 90mm wide.

Our Thule Force XT and Thule Motion XT Boxes can also have the T Track fitting installed if required.

All 3 types of clamp are very simple to attach / detach to roof bars.

The fittings (U Bolt and Thule Easy Snap U Bolt systems) at the bottom are the more basic ones which we no longer use.