Selco Products Co.: disc thermostat
The T10/T11 Series thermostats feature a bimetallic, temperature sensitive disc with a snap-action switch for contact opening and closing, designed to offer rapid and positive operation. According to the manufacturer, outstanding disc characteristics and a contact wiping action virtually eliminate contact chattering, false cycling, and sparking. According to the company, thermal and electrical insulation around the bimetallic disc prevents self-heating and ensures actuation only from the temperature of the controlled equipment or the adjacent environment. It features an operating temperature range of 104˚F to 338˚F, with differentials from 14˚F to 100˚F.
— Selco Products Co.