http://stores.silkmagictricks.com/products/set-of-4-sponge-tennis-balls-by-alan-wong.html This is the most super realistic sponge item ever made by Alan Wong. The set comes with four sponge tennis balls. You can produce them, vanish them, multiply them, throw them out for gags. They bounce off a racket like a real tennis ball too! Perfect for final loads under cups and balls - and as many as you can fit in!