It happened one evening four years ago when Cheong Choon Ng realized that his fingers were too big to make rubber band bracelets with his daughters. Ng improvised at first, making a wooden contraption to help him but, as most people with inventive minds do, he began to expand on the idea. Spending $10,000 of his own money, he marketed a plastic version of the mini loom, now known as the Rainbow Loom.

The loom wasn’t an immediate success. Ng didn’t find his first customer until almost two years later when an American franchise called Learning Express Toys ordered 24 kits: 2-inch by 8-inch looms with 600 multi-colored mini rubber bands. They sold out within two days. Since then, Ng’s company (Choon’s Design) has sold over 8 million units worldwide and is worth $130 million.

“Everybody has got this good idea [that] came about in their lifetime, and they regret not pursuing it,” said Ng. “So, I thought this would be one, and I should not let this pass by without doing anything.”

But Ng is aware that interest in the Rainbow Loom will fade with time, as many fads do. That’s why he is introducing new products including the travel-size Finger Loom. Ng also hopes to expand to new niche markets such as Germany and Japan.

But Ng reminds everyone that loom bands aren’t just for bracelets. They can be used for a variety of crafts including toys, key rings, smartphone cases, even shoes.

“The loom bands are an absolute phenomenon,” said Anna Protherough, senior buyer for children at Hobbycraft. “We began stocking the kits since they originally launched last year and since the Duchess of Cambridge was seen wearing one, they have been flying off our shelves.”

However, despite the popularity, there have been some downsides to the product. One boy lost vision in his eye after a band flew off the tool and hit him in the pupil. There have also been imitations of the Rainbow Loom which contain higher levels of chemicals than the original.

Rainbow Loom products warn: “Some fake products possess the same name as genuine Rainbow Loom products but these counterfeit products are unsafe for children and have not been tested in accordance with U.S. Toy Safety Standards [may contain lead and other dangerous substances].”

The new Finger Loom, created by Ng, will be available on Wednesday.