They'll protect your table. Coast to the final frontier with this Star Trek Lighted Coasters 4-Pack. Each 4-inch diameter ceramic coaster features a different hero from the original Star Trek TV series… and their lights change color 7 times! Captain Kirk, Dr. McCoy, Scotty, and Spock will protect the surface of your coffee table if anybody can. Require 2x "CR2025" batteries, included.