There are many other products available in this space but there is nothing similar to the Spin King.These include:
Plastic covered soft ball with a one piece moulded cover over a soft centre ball. .
A disc style device that is difficult to play with. Made from PVC in bright yellow.
A traditional two sided spin or swing ball that provides no feedback to payer on seam position.
These hard plastic discs are for bowling drills and are unable to be used for backyard play.
A traditional uneven sided swing ball for net use. Unsuitable for backyard use.
A net practice ball consisting of a leather ball with holes drilled in one side for swing.
IA pack of 3 backyard balls of varying types to work on backyard technique.
Great fun for skimming off the pool but doesn't teach kids correct bowling technique.