I have a one. June Taylor use to sell them but they were discontinued. A clapper has been used for decades by tailors and dressmakers. It is used with steam for the best results. No one will believe how great it does work until they use one. I haven't seen any in stores at all. Here is a picture so if you ever find one at a thrift store or yard sale you'll know what it is. This site has one listed for sale:
http://www.cuttinglinedesigns.com/home.aspx