Thermal Plate Fuse Link 257F -Opens On Rise at 257 degrees F.   For use on furnaces, dryers, fans, dishwashers, limits, ect., U.L.Rated, #NTDC257. 3/4" disc diameter. These face plate fuse links are new and made by Napco/Supco US Corp. 22 amps @ 277V resistive rating.