Cool Glow Mugs are Patented exclusively by Glowsource.com. Our 12oz Glow Mugs are the ideal, inexpensive solution to your glow in the dark party needs! Sold as 15-pack of mugs with collar and glow sticks. Place an activated glow stick in the bottom of the mug for instant glow. These 12 ounce clear mugs are re-usable and a great party favor to send home with your guests. These cups have a special collar that fits in the bottom. Add our colorful glow stick that wraps around the bottom of the collar to light up your cup. You can use these over and over again, buy extra super bright shorties to use for future events.and with multiple different colors.