Temperature Sending Unit1/8 in.-27 NPT ThreadIncludes 1/2 in.-20 NPT Reducer BushingFor all JEGS LED Transmission & Water Temperature Gauges Sending Unit for Gauges:555-41572555-41438555-41418555-41447555-41462555-41411555-41431555-41570555-41484555-41578555-41444555-41455Note: This temperature sending unit is grounded through the sensor so do not use seal tape or any other sealant on threads where it is attached to the engine. The gauge will not work or may read incorrectly if the sending unit does not have a good ground connection.