Oo I so remember these. They had horizontal tags to insert into sheaths. No winding just a strong memory wire that you had to free to make soft and body temp made it active. It is an American product because my client bought some back when he visited. Try googling memory wire expanders?http://orthocj.com/2000/01/maxillary-expansion-with-thye-tandem-loop-arndt-memory-expander/
Just reopened my lab for business. I closed down for a year due to my husbands health. Been in business almost 13 years now. Sole owner/operator, gonna take it a bit slower this time.