Thule Criterium Bike Carrier Upright rooftop carrier for one bicycle with secure C-clamp clamping technology Ratcheting rear wheel strap quickly secures back wheel to tray Stylish aluminum tray holds bike in place while loading Fits bike frames up to 3-3/8 inches in diameter and tires up to 2.6 inches wide Fits Thule square bars and round bars out of the box and Aeroblade/Aeroblade Edge with Xadapt8 (Sold Separately)