A General Electric toggle light switch of the silent operation type. The silent operation aspect allows the switch to be operated without noticeable clicks between "on" and "off". Although the switch is described as a "light switch," it would likely be classified under the US NEC (National Electrical Code) as an AC/DC general use snap switch (NEC 404.14(B)) with a T rating (note the "T" on the lower metal yoke.) For more information, see "Residential Electrical Wiring" by Ray Mullin and Phil Simmons, Cengage Learning, 2014, pages 166-167.