Thermostat piece (4)
I believe the answer is:
dial
(Other definitions for dial that I've seen before include "Face of a timepiece" , "Clock face" , "Indicator" , "Coil of yarn" , "Laid up like clock-face" .)
I believe the answer is:
dial
(Other definitions for dial that I've seen before include "Face of a timepiece" , "Clock face" , "Indicator" , "Coil of yarn" , "Laid up like clock-face" .)