From the kitchen to thousands of retail stores across the U.S., two sisters’ business is booming after creating a popular bath bomb business — and all before they were old enough to go to high school.

Caroline and Isabel Bercaw started Da Bomb Bath Fizzers in their parents’ kitchen when they were 10 and 11 years old, respectively. Now, six years later, their products can be found in over 15,000 stores across the nation, including Costco, Target, Ulta and CVS.

Bath bombs, which are packed mixtures of dry ingredients that bubble and hiss when wet, are used to add oils bubbles, scent or colors to bathwater.

Da Bomb saw over $10 million in revenue in 2017 and is expected to hit $20 million this year.

“When we were younger we used bath bombs all the time,” said Caroline to FOX Business’ Dagen McDowell on “Mornings with Maria” Opens a New Window. on Monday. “But we wanted to make our own because a lot of times it would stain the tub.”

So Caroline and Isabel decided to add a little “surprise” to each and every one of their bath bombs to make them appealing to a broader range of consumers and set them apart from the competition.

“It could be like a toy or a message on waterproof paper or even some jewelry,” Isabel said. “And it always coordinated with the name and the fragrance of the bomb.”