This Klixon® snap–acting disc type control is designed to provide crisp, positive switching action. The 4391 is the most versatile of the Klixon® precision thermostats with its available SPST or SPDT switching, automatic or manual reset, and overmold options. The high current carrying capacity in a hermetic package make it ideal for applications such as aircraft galley equipment, aircraft lavatory hot water heaters, semiconductor equipment, and locomotive/railcar heaters.