LED Light-up drink mug: Take up the cup, push the switch to 'ON 'position, then the LED will begin to flash. Take up the ... switch to ON position, then the LED will begin to flash.Put down the cup, The LED will stop flashing right away.Warning ... the internal electronic device from any damage.Detailed Product Description LED Coaster, Light up coaster, promotional coaster, promotion gift, Glow coaster, ...