Notes
GEM is one of the foundational American razor brands. GEM and Ever-Ready merged in 1906, incorporating as the American Safety Razor Company. That same year, abandoning the older wedge-blade design, ASR introduced the single-edge rib-back blade that is still the SE standard today.
In 1919, GEM/Ever-Ready merged with Star to become the American Safety Razor Corporation, chartered in Virginia with razor and blade production remaining in Brooklyn, NY.
GEM single-edge razors dominated a large share of the American shaving market through the first half of the 20th century, competing with Gillette's double-edge system.
GEM produced numerous models over the decades, including the Damaskeene / "1912" (flip-top, 1912–1921), the Junior (from 1933), the Micromatic (twist-to-open, from 1932), the Micromatic Open Comb, the Heavy Flat-top / "G-Bar," the Featherweight, the Flip-Top (1950s), and the Push-Button (1950s–60s).
This one is probably the Push.Button.