These days, thin is in — from slimming down with the South Beach diet to celebrities trading in their gas-guzzling SUVs for the environmentally friendly Toyota Prius, to flat-screen computer monitors and TVs. In keeping with the trend, Swistar Watch Company has introduced the Slimtek watch, “the slimmest timepiece on the planet.” At only 3.6 mm, you ain’t kidding. The watches feature quartz movement and a variety of dials, colors, and bands — including stainless steel and leather — and, surprisingly enough, with a price range of $495 to $595, the watch won’t make much of a dent in your wallet. Unless, of course, you go with one of the two new special-order luxury models in either solid gold or platinum with diamond accents (from $1,500 to $1,900), in which case your wallet might get a little thinner, too.