This potty watch is another inexpensive find through Amazon that younger kids typically find easy to use. There is a pink version with unicorns and a blue band with dinosaurs. The band is adjustable, but can be difficult for young hands to put on and off. The timer can be set for every 30, 60, 90 minutes or 2 or 3 hours. But it has to be turned off at night and charged every 3 days or so. It is water resistant to splashes, but not to pools or accidental drops into the sink. The timer alerts with lights and music, but there is not a vibrating option for kids at school where an audible alarm can be distracting.