641 Series Pushbutton Switches Carling Technologies 641 Pushbutton Switches are single pole or double pole switches that represent the most compact offerings in pushbutton switch line. Carling 641 Pushbutton Switches feature rugged metal construction, self-cleaning contacts, and a stiff actuation force for most foot pedal-type applications. These switches fit a standard 0.5' mounting hole and are available in solder lug, wire lead, and PC terminations.