The descending bubbles have a soothing and mesmerizing effect that will keep kids entertained for hours. Gravity will guide the colored droplets travel down at slow motion space. These sensory toys can help improve visual tracking skills. Its slow and rhythmic drops have a very appeasing effect and actually help kids with sensory or hyperactivity issues. Makes perfect autism sensory toys to sooth and remain focused. Endless hours of calming entertainment. Great as therapy toys and even stress relief toys. Never runs out of energy. Just flip over and start again. This liquid timer makes the perfect fidget toys, office desk toys and even as classroom rewards. Like a stress ball used for hands, these are perfect as ADHD toys for gentle visual stimulation.