The Magic Suction Cup provides strong (yet temporary) grip on most flat nonporous surface such as glass or metal. To attach the suction cup, pump the plunger until the red line is hidden. To remove the suction cup, simply pull the rubber tab at the edge of the suction cup to break the vacuum. The suction cup has a built-in female socket that can receive the 5/8" (16 mm) hex stud on various arms. An additional spring locking system in the hex receiver prevents inserted attachments from falling out when not fully secured by the screw locking mechanism. The Magic Suction Cup works best with the Super Knuckle arms because of their lighter weight. The user-friendly suction cup is easily secured and removed efficiently from any nonporous flat surface.