Small automatic reset 110F CLOSE ON RISE snap switch found in many Breckwell models often referred to as the proof of flame (POF) switch. Switch is normally open, closes when the temperature reaches approx. 110 degrees Fahrenheit (+/- 5 degrees) and resets when the temp drops to around 80F. Breckwell part no. cross reference is C-E-090-22C
Can also be used to replace the Quadra-Fire 812-4670 Snap Disk #1 on Castile stoves except the connectors are vertical rather than horizontal like the original.