Using traditional coasters to protect your valuable furniture can now be mixed with modern technology. The Sylvania LED Color Changing Coasters gradually transforms colors for an awe inspiring effect. This set of four coasters are battery powered, so no electrical cords are required. Simply remove the pull tab from the battery compartment and it is ready to use. A pressure sensitive button is located on the bottom that is activated whenever the weight of a beverage or other object is placed on top of it. Have fun using these water resistant, illuminated coasters with family members or entertaining at your next party, they are sure to be a conversation piece. Each coaster requires the use of two CR2032 batteries, included.