An instant top tube for any bike frame, you can install this adjustable Yakima TubeTop adapter between your seatpost and stem to make your bike frame compatible with Yakima hitch and trunk racks. Installs quickly and securely to seatpost and stem to create a faux top tube so your bike mounts solidly to a single- or dual-arm mounts Length is adjustable to fit many bike sizes and styles, including most kids', step-through, hardtail and full-suspension bikes Oversized diameter tubing and anti-rotation inserts provide greater stability Large molded collars are gentle to your bike's finish Measures 22 in. long by 1 in. diameter (compressed, the TubeTop measures about 14 in. long) 45 lb. capacity (for a single bike