The Robertshaw 1900 Series Thermocouples include either a special low-mass or quick dropout thermocouple. It is usually found on applications that require an oxygen depletion system on the thermo safety. It is also found on many LP gas applications that require a quick dropout of the thermo safety if there is a loss of pilot flame. The Robertshaw 1980 Series Snap-Fit Thermocouples offer easy installation into the majority of pilot burners. They are manufactured without complicated adaptors, but with extra insulation that the brass sheath provides under high ambient temperatures.