Teaching about Bernoulli's principle and air pressure has never been more fun! This unique and easy-to-use smoke ring generator is sure to be a big hit in your classroom. The donut-shaped vortex is produced by high-pressure air exiting the hole of the blaster that begins to rotate around a localized low-pressure ring. Enough non-toxic smoke-generating fluid to generate more than 25,000 smoke rings. Requires six AA batteries, not included.