<http://schema.org/description>
"While practicing your swing, have you ever wondered how that tennis ball launcher could manage a perfect serve every time?  Go to the next image to see how the tennis ball launcher looks on the inside."^^<http://www.w3.org/2001/XMLSchema#string>
<http://electronics.howstuffworks.com/gadgets/other-gadgets/tennis-ball-launcher-pictures.htm>