★ Liquid Activation: This is a transparent water-sensing cup. There will be colorful lights flashing automatically after added with liquid to glow, such as water, beverages, beer, etc. It's greatly help to build atmosphere at night parties, dating, or in bar. ★ Safe and Non-toxic: This LED flashing cup is made of high quality acrylic material, environmental protection, non-toxic and to use. It is a pretty effect as the colored light reflects off the sparkly crystals embedded in the bottom of the glass, it is a water bottle at the same time can also be used as a decorative vase. ★ Quality Assurance: All of the product are strictly inspected before shipment, so please purchase with confidence. Please contact us if there is a defective product due to manufacturing reasons. ★ Widely Application: It's a ideal choice for parties and any kind of get-together occasion, a huge access to be a hit at a party. In a lighted room, it will draw attention, and in the dim light, it is a real eye-catcher, full of and add lively atmosphere. ★ About Batteries: This light cup is powered by 2*CR2025 batteries (not included). And it's so easy to replace them. Use a dollar coin to rotate in the middle of the bottom of the cup in the direction of the arrow, you can open it, then open the small piece of iron and pour out the old battery, put the new battery and close the battery card.