Tridon Thermostat TT578-189 Blue The stop light switch is

The stop light switch is a mechanical device used to control operation of vehicle stop lights

but other brands of pads as well

either paper or rubber 'O' rings (sealing rings)

Opening Temp: 74°C

Flange Dia: 60mm

Tridon Thermostat TT578-189 Blue The stop light switch isThe thermostat is a temperature control valve assembly used in the vehicle cooling system. Located in a housing usually at the front of the vehicle engine, the thermostat allows circulation of coolant through the radiator once the predetermined engine temperature is achieved. There are various styles of thermostats available including conventional, by pass, thermostat housing assemblies, high flow and inserts used in conjunction with original housing.