The Camco mechanical suction cup hook features two hooks and installs to the interior/exterior of your RV, glass and smooth non porous surfaces. This allows you to hang a variety of items, such as wet towels and swimsuits. It suctions tightly with a twist turn mechanical suction cup design, securing your items while they remain hanging. Constructed of durable polymer, the suction cup hook is UV stabilized for a long life. It's ready to use - no tools are needed for installation.