In the wake of the preppy craze comes a product for the punk movement, a poster describing the characteristics of the "Clashous Slobus," or punk afficionado. Created by Georgetown University freshman Eric Hersman, the poster portrays, among other things, the "psychotic smirk," 1950 designer glasses and spiked wristband that Hersman says mark a true punk.

At a recent convention of college bookstore owners, Hersman says he sold more than 20,000 of the posters to a national record chain and other major distribution deals are in the offing. With expenses of $2,500, and a wholesale price of $1.25 per poster, Hersman may profit handsomely from ugliness.

"I think punk is a growing fad that can be exploited to the maximum potential," says entrepreneur Hersman, the 19-year-old son of a Washington lawyer. "If I make $100,000 doing it, that's fine with me."

Actually, Hersman confesses that he's more preppy than punk. He favors tassled loafers and blue blazers, so he had to do some research for his poster. tIt was while he was working at his desk in his Spring Valley home (Hersman hopes to study business at Harvard eventually) that he looked up at his preppy poster and decided to do the same for punks. He interviewed young men and women waiting to see the punk fashion crowd's favorite movie, "The Rocky Horror Picture Show." And it was near the theater that he found Eric Vesper. Hersman paid young Vesper $100 to model the punk look for the poster and three days after he designed it, the poster was off the presses.

Hersman says with overseas sales he could make $250,000, but just in case the punk market isn't lucrative, he's poised to penetrate the preppy biz. Along with friends, he's writing a preppy almanac that features something preppy to do every day of the year somewhere in the country. Also on the drawing board: The Preppie Drink Book, which flaunts a cover of an alligator holding a cocktail.