The T4398A1021 from the Honeywell T4398 Series is a non-programmable heat thermostat designed for working with applications like electric baseboards, convectors, and fan forced heaters.The T4398A1021 from Honeywell is a non programmable heat thermostat from the T4398 Series is to be used with Electric Baseboard Heat. The model comes with a thermometer, range stops, and locking cover screws. This high quality thermostat has the capacity to handle line voltage control of resistive-rated electric heating equipment. It is best used with electric baseboards, convectors, and fan forced heaters. It is very sensitive to temperature systems and includes a heavy duty plastic mounting base.