1----Reliable Material: The light up coasters are made of high-quality clear acrylic, lightweight and durable, safe and eco-friendly. Note: Please do not soak in water. 2----Brilliant and colorful: LED coasters emit charming colorful lights, creating a cozy and surprising atmosphere, perfect for bars, dinner parties, cocktail parties, bonfires and any evening parties, making your evening stand out. 3----3 Lighting Modes: This glowing coaster has 3 modes for you to choose: fast flash, slow flash and steady mode, a variety of light effects to meet your different needs. 4----Battery powered: The luminous cocktail coasters are powered by 2 CR1620 button batteries, which can last for 8-10 hours, you can replace the batteries by yourself, just carefully tear off the sticker, then take out the old batteries and replace them with new ones. 5----Dimensions: The LED light up coasters are 10cm in diameter and 10mm thick, suitable size for most cups, mugs or wine bottles. Note: Please do not soak in water. Features: Material : Transparent acrylic + electronic components packed with box Size: 10*10*1cmLight colour: coloured, white3 light modes: slow flash, fast flash, constant lightBattery capacity: 400mah polymer batteryShape: octagonal, square, round