If you've ever spent a hot summer day lounging in a swimming pool, chances are that you propped yourself up on a pool noodle—that foam tube that has a seemingly endless variety of ways to keep you afloat. While the concept is genius in its simplicity, its invention is fairly recent—and contested.

There are reportedly two men credited with the invention of the pool noodle. The first is Canadian Steve Hartman, the CEO and president of Industrial Thermal Polymers. More than 30 years ago, Hartman went into business with his father, who wanted to make backer rods—the foam tubes used in construction projects to fill in the gaps.

"We always had these foam rods (lying around)," Hartman told Marketplace. "They were gray and nine-footers and it seemed like every time we jumped in the pool, we were playing with these things.”

Soon, Hartman added a splash of color to the rods and attempted to sell them to various stores as a pool toy. His pitch was simple: "We said, 'Well, you float around with them, you hit your brother with them.' It was a tough sell."

Their ally was unexpected—Canadian Tire. The all-service store priced them incredibly low, and they started flying off the shelves. According to Watercrunch, the popularity of the innovation spiked in 1987, when Canadian Tire made a big order for the product. By the mid-1990s, the noodle had gained a following in the United States. Today, Hartman’s success is evident. His company sells 6 to 8 million noodles per year.

But another Canadian, Richard Koster, also lays claim to the pool staple, which he calls the Water Woggle. In 1986, after developing a "pull buoy" to assist swimmers, Koster used the foam components to create foam rods. He encouraged his children to play with the rods in the backyard pool and quickly realized the marketing potential of the project.

While three other companies were producing tubes with white foam, Koster reportedly used tape to make his colorful. By 1987, his solid-colored Water Woggles hit the North American marketplace.

Neither Koster nor Hartman ever applied for a patent, thus other companies are able to produce similar pool toys. "It was our idea, our product," Koster told People in 1995. "But you can't take that to the bank."

Regardless of who the genius behind the pool noodle was, there’s no questioning its staying power. WaterCrunch cites it as the most popular pool toy in North America, noting that annual production on Hartman’s product begins in November.