Thermal cutoffs and thermal protectors are nonresetting, thermally-sensitive devices that are designed to protect electrical appliances and industrial equipment from fire. They are sometimes called thermal one-shot fuses. When ambient temperature is increased to an abnormal level, the thermal cutoff senses the temperature change and breaks the electrical circuit. This is accomplished when an internal organic pellet experiences a phase change, allowing spring-activated contacts to permanently open the circuit. Consequently, cutoff temperature is one of the most important specifications to consider when selecting thermal cutoffs and thermal protectors. Other important considerations included cutoff temperature accuracy, voltage, alternating current (AC), and direct current (DC).