Simple pieces of slick, padded plastic are turning a West L.A. celebrity trainer into an international businesswoman.

Valerie Waters developed her ValSlide device five years ago as an alternative to bulky slide boards. They retail for $30 and they’re used by such clients as “Alias” star Jennifer Garner and “G.I. Joe’s” Rachel Nichols. The sliders enable exercisers to do intense training wherever they might be.

“It kicks your butt, but it’s light enough that you can put it in your bag and use it in a hotel room or set trailer,” said Waters, who made her reputation readying actors quickly for roles requiring buff bods.

In a lunge, for example, users place the discs under their sneakers and then slide back and forth, exercising the quadriceps. ValSlide also can be used for buttock and abdominal exercises.

Like other celebrity trainers before her, Waters is leveraging her Hollywood success. Among her projects are a series of video training programs and an Internet-based coaching service. She’s holding her first event on Sept. 25 in West Hollywood, with a speaker list that includes Garner’s skin care consultant and Kim Kardashian’s hair stylist.

After recent coverage in the Wall Street Journal and on “Good Morning America,” Waters has signed on a number of business executives. She’s even sold the devices overseas through her website, and has received feelers about an infomercial.

“I’m exploring opportunities, but for now I enjoy having control of a company that I built up myself,” she said.