The Honeywell-T6031A1136/U Refrigeration temperature controller is used to control temperature within a certain range of temperature -30°F to 90°F. This SPDT controller comes with an 8-foot capillary tube that measures the temperature within the refrigeration unit and relays this information to the controller. https://www.partshnc.com/t6031a1136u-honeywell-temp-control-3090f-spdt-8-cap