(FORTUNE Magazine) – A new Christmas catalogue is in the mail that bears a familiar, but hardly seasonal, message: ''Buy American.'' The Union Label Shopper offers union- made products at prices 10% or more below retail to the 14 million AFL-CIO members. The modest catalogue, which is a two-sided poster, is the work of American Union Shopper Corp. of Fairfield, Iowa, a for-profit company formed to tap the buying power of unionized workers. Since the company introduced the catalogue in some 8,000 union publications last August, it has received more than 175,000 requests. The AFL-CIO verifies that the catalogue's items, ranging from denim overalls and wet/dry vacuum cleaners to popcorn poppers and coffee makers, are union made, but it gets no cut of the company's sales. Mail-order merchandising to special-interest groups has often yielded good results. To support environmentalist causes, the Sierra Club has long used the post office to sell such items as books, calendars, and T-shirts. Greenpeace, an antiwhaling organization, has sold mail-order items with whale motifs for years. Will the AFL-CIO's predominantly blue-collar members buy through the mail? Will they have enough money to do so? American Union thinks so and is already planning a second, 24-page catalogue for January.