The stem type thermostat sense the temperature by thermal expansion coefficient difference of copper rod and nickel rod, and the double pole safety cutoff controlled by bimetal disc, it’s suitable for storage electric heater. Easily install, it can be directly inserted into the special water heating element, to replace a liquid expansion thermostat and a protector, saving the connecting wires and additional mounting. It can be preset the operating temperature in factory, and adjusted the control temperature by end user, and with multi-position temperature control function. With the feature of easy control, convenient operation and low cost, it’s the another design option for storage electric water heater.