Radioactive Elements Glowing Coaster Set We love chemistry, so we really light up when we talk about this product created at ThinkGeek: our Radioactive Elements Glowing Coaster Set. Featuring the atomic number and isotopic mass of the most stable or common isotope for their respective radioactive elements, these pressure-sensitive coasters light up when you put your drink on them. Choose to set your drink down on: Radium-226 (Red) Plutonium-244 (Blue) Uranium-238 (Green) Thorium-232 (Orange) Set of four comes in a box with the radioactivity warning symbol. Batteries included. Product Specifications Coasters that light up when you put your drink on them Perfect for the chemist in your life Great for parties - easily remember which drink is yours Feature the atomic number and isotopic mass of the most stable or common isotope for each element Materials: Plastic Batteries: 8 3V CR2032 batteries (included) With constant use, batteries last c. 4.5 hours Dimensions: 3 3/4" square, 1/4" thick Weight: 3/4 lb. (set of 4) Not dishwasher safe Note: The coasters used in the video were an (incorrect) sample. They still look and work exactly the same- except for the "95" on Uranium, which has since been corrected to 92.