The Rinnai 1004F-2057 is a genuine Thermistor Lead Assembly for 1004FA. Thermistor with lead wire that tells the control board the temperature. Replace when the furnace reads temperature wrong or shows a sensor fault.
This is an OEM Rinnai part, so it fits and performs the way the original did. Confirm your model before ordering; the model is on the rating label on the unit. If you are not sure which part you need, Rural Energy support can check it against your model and serial number.
Rural Energy is a Rinnai distributor and keeps Rinnai direct vent wall furnace parts in stock for fast shipping to dealers, contractors, and homeowners.