KSD301 is a universal snap button temperature protector. A temperature controller using bimetallic strips as temperature sensing components. When the electrical appliance is working normally, the bimetallic strips are in a free state and the contacts are in a closed/open state. When the temperature reaches the operating temperature, the bimetallic strips generate internal stress due to heat and quickly move, opening/closing the contacts and cutting off/connecting the circuit, thereby controlling the temperature. When the appliance cools down to the reset temperature, the contacts automatically close/open and return to normal working condition. Its main application scenarios are: electric water heaters, water buckets, sandwich toasters, dishwashers, dryers, disinfection cabinets, microwaves, electric coffee makers, electric boiling pots, refrigerators, air conditioners, glue machines, office equipment, car seats, etc.