This air cartridge is COATED/COATED. The magnet sticks too strongly to the stem for this component to be made of stainless steel! Yes, I know most stainless steel is magnetic to some degree. But not like this! I use the same magnet to test all metals and have known good samples for comparison. The collet end and FNPT head, on the other hand, are nowhere near magnetic enough to be any steel, stainless steel or anything else. Probably brass or zinc on the FNPT end and almost certainly zinc on the head. You can even see built-in fairings/trims on it. The ads are not only an outright lie, they also appear cheap. As; dollar store cheap. I don't even have to return it to get a refund. Revain should PAY ME just to throw this thing in the trash!