The thermal cut off is an emergency kill fuse of the heating component when the dryer overheats. The bottom larger thermostat is ensuring there is a consistent level of heat at all times and will constantly cut on and off. This 279816 dryer thermostat kit includes one thermostat with a limit of 250 degrees Fahrenheit, and one thermal cut-off fuse (309 degrees). This kit also includes a jumper wire, screws, and an extra terminal end. Make sure to check your dryer ventilation as in many cases if this is stopped up or blocked in any way it can cause issues. This is not a Whirlpool OEM product. The Whirlpool brand names and logos are the registered trademarks of their respective owners. Any use of the Whirlpool brand name or model designation for this product is made solely for purposes of demonstrating compatibility. "The trademarks, logos, and service marks (collectively the "Trademarks") displayed herein Supplying Demand are registered and unregistered trademarks of Supplying Demand, its affiliates, and others. Nothing contained herein should be construed as granting, by implication, estoppel, or otherwise, any license or right to use any trademark displayed herein without the written permission of Supplying Demand or such third party that may own the trademark displayed herein. Your misuse of the trademarks displayed herein, or any other content on this website, except as provided herein, is strictly prohibited."