Neoprene. It sounds like something you might put in your gas tank, but it's really the hottest suit at the beach this season—in every respect. Earlier this year, curvaceous model Elle Macpherson sported a black, thigh-high neoprene number on the cover of the Sports Illustrated swimsuit issue, and at that point there was no turning back. From the chichi Hamptons to the funky boardwalks of Venice Beach, America's tautest bodies are now on the prowl in skimpy somethings made of rubbery stuff that used to be strictly wet-suit material.

"There's something escapist in the look—attractive, sexy, adventurous," says Macy's fashion director, Joan Kaner. Observes Robin Piccone, designer for Body Glove, a Los Angeles-based manufacturer that was first on the beach with neoprene in 1986: "Women who wear these suits look like they belong in a James Bond movie." This year Body Glove, now competing for the wet-suit-look market with Too Hot Brazil and Jag, expects to pull in $12 million from neoprene alone.

Basic frogman black is a favorite with customers, but so are suits in Day Glo colors including fuchsia, lime, yellow and turquoise. Besides the classic one-piecer, neoprene also comes in bustier bikinis and cropped tops with tiny, zip-front skirts. Prices are generally in the $50 range.

The look may be chic, but the style has its drawbacks. Pure neoprene is too heavy for sunbathing, so manufacturers were forced to cook up a thinner version—a rubber product bonded to nylon. Yet even the substitute is for masochists only. The fabric doesn't breathe, and on hot days it tends to deep-fry the wearer. Some women have complained that the synthetic rubber gives them rashes. "Neoprene isn't real comfortable," concedes Katy Nishida, a Santa Monica teenager. "It's mostly for looks. But it's very sexy."

If neoprene survives in the swimsuit market, vanity will deserve all the credit. Among other things, the fabric offers the old-fashioned control Grandma used to get from a girdle. "The better your body, the better you'll look," advises Joan Kaner, "but these suits offer support. No one has to be centerfold material to wear them."