Acrylic drafting rules, 1939

Andrea DiNoto, Art Plastic, Design for living, Abbeville Press, New York, 1984

Although the first discovery of acrylic acid dated to the mid 1800s, acrylic as a plastic material was developed by the British company ICI (Imperial Chemical Industries) in the early 1930s who trademarked it as Perspex. The plastic industry responded and soon afterwards, versions of the material were marketed in Germany by Rohm and Haas as Plexiglass and Dupont in the US as Lucite. 
The drafting tools shown above were among the first products on the market, produced by a German company (whose name I can't quite make out) in 1939. 
 The crystal clear and strong material was embraced by the newly busy aircraft industry, transforming the design of canopies and turrets.