Temperature Sticks are used to determine a thermostats operating range, by rubbing 87°C (188°F) and 97°C (206°F) sticks on the thermostat housing. They feature economical & versatile, convenient pocket clip and fahrenheit/celsius selectable. Temperature sticks are designed to melt at certain temperatures and applied to the surface of the metal. These temperature sticks mark the surface of the piece to be heated with the appropriate temperature.