Classic dial thermometers use a bimetallic spring-like coil attached to a pointer. As temperature increases or decreases the pointer rotates around a fixed dial. Made in France.
These were purchased from Wisconsin Clock Co. in Hortonville, Wisconsin when they decided to close their business. They were a clock parts distributor and manufacturer of grandfather clocks and expanded into many different types of clocks and markets as well.
Measures 2 3/4" in diameter by 1" thick. Behind the dial, 3/4" thick.