Back to the future: A fabric that permits suntanning is making the rounds of Seventh Avenue. Developed by a military contractor, Inner Tech Inc. of Richmond, Va., the material is being used on hat brims by the designer Patricia Underwood.

"It's a tan-through polymer that keeps out 90 percent of the UVB rays," said Don Carter, the marketing director of Sanctuary Fabrics, the fashion division of Inner Tech, which makes light-altering fabrics for the military.

Imagine walking around the city fully clothed and getting a tan. Why, it's almost like being naked!

The polymer fabric, which feels like a plastic tarp, screens out the burning ultraviolet B rays and permits less-harmful ultraviolet A light, which can tan. Unlike tan-through swimsuits, which use a knit fabric with tiny pores in the surface, the Sanctuary material actually separates the two kinds of light, like a sunscreen. It's rated SPF 10.

Mr. Carter said his company had received a request for some fabric from Chanel in Paris. "For what purpose I have no idea," he added. The real advantage would be to turn it into swimsuit material. Nothing worse than those unsightly tan lines.