(FORTUNE Magazine) – After being offered cigarettes that are longer, slimmer, and lighter, smokers may soon have the novel option of dialing their preferred taste. Philip Morris has launched a four-city test of Concord, a cigarette with an adjustable filter that lets the consumer choose the strength of the flavor with a simple twist. The new cigarette, in regular and menthol flavors, can deliver five milligrams to 15 milligrams of tar -- the main determinant of a cigarette's flavor. Philip Morris, the largest cigarette maker in the U.S. with its Marlboro, Merit, and Virginia Slims brands, is assuming that enough smokers will want to vary their intake of tar to create a market for Concord. ''There are times when a smoker wants a light cigarette or a more full-bodied cigarette,'' says Thomas Keim, director of marketing communications for Philip Morris USA. ''We think it's a good enough idea to explore.'' With more than 265 brands on the market, a bright new idea may not be enough to make a new product successful. That's why Concord is being tested in a few markets. This year the company aborted a test of Reo, a menthol cigarette in a red package, after it discovered that smokers expect menthol cigarettes to come in green wrappers. Industry reaction to Concord is also cautious. ''It's a novel concept,'' says Diana Temple, tobacco analyst with Salomon Brothers. ''Maybe they'll find a definable market segment.'' Any new market segment is welcome at a time when health-conscious Americans are kicking the habit. According to the American Cancer Society, 34.8% of U.S. males and 29.1% of U.S. females over 20 smoke, vs. 41.6% and 32.5% nine years ago. But if a smaller percentage of Americans are smoking, those who do may be lighting up more often: that factor plus population growth account for the fact that in recent years the number of cigarettes sold has remained almost constant at 600 billion.