Part One - Federal Trade Commission Website
Name of Company: Act III. There is a (R) near the lower corner of the registered trademark and a WPL number.
History: WPL numbers were issued from 1941 through 1959 under the Wool Products Labeling Act. WPL numbers begin continue
Another hint from the label are the words Dacron Polyester, which was used 1958 to 1970.
Federal Trade Commission Website
So, I enter just the number and then click "find"
1) It gives the researcher more information including names of owners or company names and addresses that were not on the garment's tag. This information will help the researcher confirm other searches and expand his or her knowledge.
2) Sometimes an identifying tag is missing or cut out of a garment, but sometimes, the RN or WPL tag or number remains. Searching the number can tell the researcher the maker of the garment and information to help learn more about the history of his or her vintage clothing.