Q-Flex was created by 13-year-old Andrea Cao, who says she’s been selling the device door-to-door. It’s a personal acupressure device, and she came up with the idea when she was too busy to give her mom a massage each evening after mom’s hard day at work.

Andrea’s mom, Hong, has an engineering background, and was able to offer some assistance. Between them, they created the flexible device that, like a back-scratcher, allows the holder to access hard-to-reach points on her own back. Unlike a back-scratcher, though, it’s designed to put pressure on points that are said to relieve muscle aches.

Andrea put on a great talk for the sharks, and it was clear by their faces that she had charmed them. But, would they invest? Would they buy into an accupressure device?

The teenager wowed the sharks further when she told them she’d already sold 800 of the devices on her own, door-to-door and by word of mouth. She’s filed for a patent on the design.

She’s asking the sharks to invest so she can have a mold made in order to produce more product more quickly. She and her mother have already invested $20,000 in the product, and has made about the same amount in sales.

Kevin O’Leary asked whether Hong Cao would be quitting her job to run the company full time if they received an investment. Saying that the product was more of a family hobby than ready to be a full-time company, he bowed out.

Saying she’d tried to sell a similar product before, Lori Greiner stepped out, too.

Robert Herjavec was third to bow out, saying he was impressed with Andrea, but not with the product.

Barbara Corcoran and Mark Cuban agreed, though, to make an offer. $25,000 for 25% of the company, and they also said they’d run the company, as long as the mother and daughter team agreed to be on call as needed. Naturally, Hong and Andrea accepted.

Final deal: Barbara and Mark jointly invest $25,000 for 25% of the Q-Flex brand.