By the numbers

Chester Greenwood

15: Age when he designed his first pair of “ear protectors,” in 1873

19: Age when he acquired a U.S. patent for them

30,000: Pairs of earmuffs produced by his company in 1883

400,000: Pairs of earmuffs produced in 1936, the company’s biggest year

Source: www.maine.gov, www.ideafinder.com/history/inventions/earmuff.htm