This product is an innovative tool that will alert you when you've reached 210°F (100°C). At this temp you should cease heating a main shaft, flywheel sprocket shaft, motor, or transmission case. To remove stubborn bearings, races, or gears, just apply heat strip next to the race on the shaft you're heating and watch the strip change color as you reach 210°F. These heat temperature strips come in a 30 piece heat strip pack.