... drive switch on/off action, the purpose is to achieve constant temperature.WYHseries thermostats have temperature control accurate, reliable, smalldifferential, temperature adjustment range, and large ... .Usage:to beapplied tokitchen freezer, chiller, refrigerator, icemachine, fishpond for temperature control use.Usage: to beapplied tokitchen freezer, chiller, refrigerator, ice machine ...