Selco CA/OA Series Bi-Metallic Thermostats Professional range of CA/OA series thermostats from Selco. These thermostats utilise a temperature sensitive disc, electrically isolated from the switch. The entire switch is enclosed in a dust free housing. Contacts open or close on rise when surface or temperature increases to the snap point of the calibrated bimetal disc. The bimetal disc is retained by a mental heat-conducting end cap. All CA/OA series thermostats are used for various applications and are highly reliable and excellent quality. Thermal Switches