Limit Thermostat- 1/2" disc diameter - Manual Rollout, (300F) - Cut out at 300F. Manual reset. For use on furnaces, dryers, fans, dishwashers, heaters, package units, limits, ect., U.L.Rated, #RL300. These limit thermostats are brand new and made by Napco/Supco Corp.

Picture is RL220 but listing is for RL300.