This product light principle for the RGB (red, green, blue) seven color, gravity sensor button light, cycle flash method. Use the steps: install the battery, on the table - put the cup - coaster light - take the cup - coaster off. Type: LED Luminous Coaster Material: ABS Model(Optional): 1. White Shell + White Light 2. White Shell + Colorful Light 3. Black Shell + Colorful Light 4. Black Shell + White Light Power: 3 x AAA Batteries(Not Included) Size: 2cm x 9.5cm/0.79" x 3.74" (Approx.) Note: Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x LED Luminous Coaster