They need to make some with bells…

Gregg Miller proves you can make a fortune with anything. Even dog balls.

Not the kind you throw around playing in the dog park.

“What I’m doing is I’m developing testicular implants for pets,” Miller tells CNBC.

The 64-year-old inventor and entrepreneur created Neuticles, silicone implants for male dogs to replace testicles after neutering, so that a dog’s appearance…down there…doesn’t change.

Do dogs care about this? “Yes, they do,” Miller says.

Certainly their owners must. Over the last 20 years, Miller claims he’s sold over 500,000 sets of Neuticles. The average pair costs $310, though some cost a lot more, like the $2,800 watermelon-sized custom set Miller made for an elephant in a zoo.