Whenever there’s a problem, there’s always an opportunity. When Rebecca Rescate had a cat and hated cleaning litter boxes, she came up with CitiKitty, a device for training a cat how to use the toilet. CitiKitty has now sold over 300,000 units.

CitiKitty targets cat owners who live in the city and hate cleaning litter boxes, like herself. The product consists of concentric circles that owners can remove to gradually train the cat to use the toilet. As the cat gets more familiar with using the toilet, you can gradually remove the circles until the hole is large enough for the cat to get directly into the toilet.

To learn more about the origins of CitiKitty, click here.