Whilst I knew that Duperite branded buttons were made for the military, I did not realise they were also advertised in the Daily Mercury (Mackay, Qld) from 1943-44:
Fashion Pfeiffer/ R.A. Pfeiffer
There were two associated clothing manufacturing companies. Mr Pfeiffer was Rudolf Alfons Pfeiffer, born in Berlin in 1902 but fleeing to Australia in 1939. He was naturalised, and enlisted to serve in WW2. He died in 1957 with his company in liquidation by 1964.
You may have some of these buttons in your collections. The pearl and plastic tricorne example was used in an article suggesting the use of buttons to make earrings!