This is a replacement thermostat for all of our XTreme Power machines that have inline heaters. There are 2 thermostats per heating element (4 thermostats per machine). Replace a defective thermostat to allow a non-functioning heater to start working again. These can also be used to replace the old manual-reset thermostats from older machines as well. These will trip at 210ºF and will prevent the heater from getting too hot. Once the heater cools down, these thermostats will reset themselves and allow the heater to start working again.