Today on our 2013 Chevy Suburban, we'll be test fitting the Thule Sonic Medium rooftop cargo box with 13 cubic feet of space, glossy black in color, part number TH634B. With a factory roof rack on our vehicle, we'll begin our test fit by placing the cargo box up onto the vehicle's cross bars. After positioning the clamps over the bars, we'll unlock the box and open the lid exposing the two closest… see more >