One of the most sought-after items in the winter clothing market - whether for hunting, skiing or outdoor living - is down, the light, fluffy filaments that form the undercoating of waterfowl.

Costing anywhere from $17 to $22 or more per pound, down is one of the best insulating materials known. A jacket, coat or vest filled with down should keep even the most particular outdoorsman or sportswoman warm in the coldest weather.Unfortunately, the high value of down is causing many unscrupulous clothing manufacturers and sellers to misrepresent inferior products as being down filled when, according to Utah Department of Agriculture officials, they are actually filled with a variety of substances - from coarse duck feathers to synthetic materials.

To legally display a label that says "down filled," a clothing item, bedspread, comforter, sleeping bag or pillow must contain 80 percent down. This 80 percent may include 70 percent down clusters and 10 percent down fiber. The other 20 percent may be waterfowl or non-waterfowl feathers, feather fibers and residue.

Darwin L. Stone, program administrator for the inspection of bedding, upholstered furniture and clothing in the Utah Department of Agriculture, said most manufacturers who display a "down filled" tag on their products have actually used the legal amount of down.

He said the problem comes mostly from manufacturers who use labels that specify "100 percent down," "down," "80 percent down," "70 percent down" or something else other than the magic words "down filled."

Stone said buyers can usually rely on famous companies or brands to deliver what they say they do when they sell clothing with a label that says "down filled."

Off brands and unfamiliar clothing makers or clothes that have no labels should be suspect if they do not have the "down filled" label. "Sales people often, sometimes unknowingly, tout winter jackets and sleeping bags as down filled when, in fact they are not and the labels even say they are not," Stone said.

"I'm not saying 50 percent or 70 percent down is bad, but it is not enough to earn the legal definition of down filled.

"If a sleeping bag has two or more pounds of down in it, you can bet it will be expensive. A good goose-down-filled jacket can cost $250 to $500 or more. Watch out for so-called down jackets that sell for $35 or sleeping bags that are supposed to be down filled that sell for $40 or $50."

Stone said shoppers may be able to get a warm, comfortable sleeping bag or jacket made with synthetic materials for a lot less money than a real down-filled product, but down has a certain romantic flavor for a great many people "and they won't settle for anything else."

Often, too, sleeping bags are advertised as being "comfort rated" to 0 degrees or from minus 20 to 50 degrees, Stone said.

"There is a great deal of leeway in these figures, which, for the most part, are simply subjective judgments. One company told me they put a man in different sleeping bags in a cold room for 15 minutes to an hour or more to see how comfortable he is in each product.

"Your body type or your ability to withstand cold may not be anywhere near the tester's, so what he calls comfortable may be unsatisfactory for you. In the second place, what might be comfortable for a half-hour or two hours may be downright frigid after a night on a windswept mountain."

Generally, he said, you get what you pay for. "Bargains aren't always the best way to go in the long run. Sometimes you really can get a good deal from a closeout or a special sale, but, as always, let the buyer beware."