It is a 91-94 SER head temp sensor, that you can buy at Nissan. 91-94 SERs came original from factory with the red sensor. Sometime in 99 or so Nissan changed the color of the head temp sensor to blue for the 91-94 SERs
The head temp sensor JDM or USDM are the same.
There is only a diffrence in the guage temp sensors