Just add liquid to activate the flashing multicolored LEDs in the base of the cup. The lights turn off when the cups are empty. When activated, the LEDs flicker, change color and glow in a beautiful changing rhythm that is sure to delight. PERFECT FOR PARTIES AND SPECIAL OCCASIONS - Best drinkware party favors or decoration for Christmas, New Years Eve, birthdays, weddings, shots, bars, night clubs or discos. ELEGANT CUT GLASS DESIGN - The sparkly pineapple crystal style design show off the blinking LEDs for a cool Lowball glass your guests and friends will remember and covet.