NPT means National Pipe Tapered. The Camco elements are NPS (National Pipe Straight) threaded. If you are trying to screw the element into a NPT fitting, it may not go all the way in before binding. I had that problem with my first RIMS chamber.paulgcorfu said:see the spec minimum tank diameter 15".I fitted one in my 70 litre pot diameter 45 centimeters.
I can also confirm it is 1" npt thread