These Glo cudes are sure to get the party started as they light up each drink. There are no buttons to press, nothing to do. Simply drop Glo in your favorite drink, and it'll do the rest. Glo uses patented technology to detect liquid - drop it in a beverage, and it comes on. Finish a beverage, and Glo turns back off - and is able to be reused again later. The batteries are non-replaceable, however each cube has a 8+ hours of active use.