Super stor age

Can someone please let me in on how to determine the age of a super stor ultra SSU-45

What is it?

I presume it’s a water heater, but I don’t know their date code matrix.
HTP makes them, give them a call and see what they say. (800-323-9651)


Hot water heater/ storage tank, seems like these questions always pop up on a weekend when most companies are closed.

SupoerStor hot water heater made by HTP. I’ve figured out that the 4th digit, in this case M, is the year code. I just can’t find a key to the code that I trust. Does anyone know the HTP year coding system?