This Kwik slide fastener dates from roughly 1932-1936. It is found on a men’s bathing suit with a zip-off tank top, a detail found in the transitional period between one or two piece suits and the topless look for men of the mid ’30s through present. The patent numbers correspond to patents no. 1814244, granted in 1931, patent no. 1752111, granted in 1930 and 1761385, granted in 1930.