These men's garters were very typical of the 1920s, 1930s, and 1940s
in the USA. Boys started to wear them the minute they graduated from
shorts to long trousers because the socks of the period had no elastic
knitted into the tops and would not stay up without garters. Some garters
had two clasps on each leg and some only one (like the example here).
But garters for men and older boys (those with long trousers) were considered
necessary for anyone who was well dressed. The garters are made of wide
elastic webbing with a pad where the connection around the leg beneath
the knee comes so that garters wouldn't be uncomfortable to wear and
irritate the leg. One of the main brands, Paris garters (made by the
same firm, Stein, that made Hickory children's supporters) had the motto:
"No metal can touch you." The fastener for the top of the sock was exactly
like the fasteners on garter waists (or German Leibchen) or for long
stockings - with a rubber button and metal loop.