1、SAFETY MATERIAL: Liquid activated multicolor LED tumblers are made of sturdy acrylic plastic for safety and sturdiness. 2、LIQUID ACTIVATED DESIGN: You just need to add liquid to activate the cup. The light turns off when the cup is empty. 3、7 COLOR CHANGING: When light up cups are activated, the LEDs will blink, changing colors, which is sure to delight. 4、BATTERY POWERED: The automatic water activated LED glass cups use a 300mAh battery with a luminous duration of 40 hours. 5、PERFECT GIFT: Best drink cup, party favor or decoration for Christmas, New Year's Eve, Birthday, Wedding, Bar, Nightclub. 1 x Liquid Activated Multicolor LED Tumblers Item Type: Liquid Activated Multicolor LED TumblersMaterial: AcrylicFlash Mode: Water SensingFlash Color: Seven ColorsLuminous Duration: About 40 HoursBattery: 2 x CR2025 300mAh (Included)Gross Weight: Approx. 164g/ 5.8oz