This prismatic color wheel is a beautiful solution to get your daily dose of color therapy. The Tät Tat Color Disk is a prismatic color wheel that attaches to any window. Rotate the 12 paper-discs randomly or stematically to create countless shades of various prismatic colors. The Tät Tat color disk easily attaches to your window with a suction cup (included). Designed by Brigitta and Benedikt Martig-Imhof for Tät Tat in Switzerland. The Tät Tat color disk is made of vellum paper and PET plastic with a suction cup. It measures 4.7" (12 cm) in diameter.