In the United States, Federal Trade Commission regulations require that any product labeled "100% Down" must contain only down feathers, while products labeled simply "Down" can contain a mixture of fiber and feathers. In addition, products labeled as "Goose Down" must contain at least 90% goose down, 10% goose feathers. Down insulation is rated by fill power, which is the number of cubic inches displaced by a given ounce of down (in3/oz). To measure fill power, an ounce of down is placed into a graduated cylinder, and a small weight is dropped in on top of it; the volume below the weight indicates the fill power. Eider down has the highest fill power, at 1200. However, even down with a fill power as low as 550 still provides reasonably good insulation. Higher fill-power downs will thus insulate better than lower fill-power downs of the same weight. Insulation in most outdoor equipment ranges from about 400 to 900  in3/oz (230–520 cm3/g). Down rated 500–650 in3/oz (290–375 cm3/g) is warm enough and light enough for most conditions, and 800–900 in3/oz (460–520 cm3/g) fill is used for very lightweight and/or very cold-weather gear.