Today on our 2008 Mercury Mariner, well be test fitting the Thule Mother of all Baskets Rooftop Cargo Carrier part number TH690XT. To install the cargo carrier fit it on your crossbars and put it in line with your vehicle. Once you have it the way that you would like it situated, swing the clamps under the crossbars and tighten them down using the gray twist knob. Once you have all four clamps… see more >