Cohn's 6 o'clock Lager was produced without alcohol so that it could be sold legally after the six o'clock closing time.
Six o'clock closing time was introduced in Australia during WWI, compelling public houses to stop serving alcohol at 6pm. It was designed to improve public morals and support women at home. However, the law inadvertently encouraged binge drinking, which came to be known as the six o'Clock swill.
The label includes the Australian Red Ensign on the left hand sign, which is the flag under which Australians fought in both world wars. You can also see imprinted above the label the bottom of the words "Swan Hill". The Swan Hill factory was established by Leo Cohn in 1923, so this bottle must have been produced after 1923.