A device for attaching accessories to a vehicle roof bar, the device comprising, a threaded control rod, two threaded nuts threaded onto the control rod, two guide bodies, wherein each of the guide bodies has one of the threaded nuts positioned within the guide body, a C-shaped rail, wherein each of the guide bodies and each of the threaded nuts are positioned within the C-shaped rail; two jaws, each of the jaws being attached to one of the guide bodies and a first portion of each jaw being located outside the C-shaped rail, whereby rotation of the control rod in a first direction causes the guide bodies to move towards each other thereby allowing a second portion of the jaws to contact the vehicle roof bar, and where further rotation of the control rod in the first direction locks the guide body within the C-shaped rail.