The Rheem Hot Water Thermistor with O-Ring, part number RTG20329M, is a crucial component designed for Rheem tankless gas water heater systems. This specialized thermistor, equipped with an O-ring for secure installation, accurately measures the temperature of the hot water output. Engineered for reliability and precision, it ensures consistent performance and optimal temperature control. Specifically tailored for Rheem units, this thermistor guarantees reliable functionality, providing efficient and dependable hot water supply for residential and commercial applications.