Today on our 2013 Ford F250, we'll be test fitting the Thule Sonic Medium rooftop cargo box, part number TH634B. We'll begin our test fit by placing the cargo box onto the vehicle's load bars. After positioning the clamps over the top of the bars, we'll unlock the box and open the lid, exposing the two closest knobs. We'll then turn the knobs to bring the clamps up around tightly against the… see more >