The light up cups use acrylic material instead of glass, making them stronger, more durable, and less likely to break. The transparent color allows the cups to clearly display the color when the button is switched on. Simply add liquid to activate the flashing multicolored LEDs in the base of the cup. The lights turn off when the cups are empty. These LED drinking tumblers are perfect as party favors or decorations for nightclubs, holiday parties, birthdays, weddings, sporting events, festivals, night events, bars, and more. They will light up the event and make your occasion memorable. Customization is available.