I'm going to stick with the 501. I had thought 502 was pretty much the same thing, and I think it is, but supposedly it was for the production level. Dealer I bought from, doesn't carry the 501, but does carry the 502. It was a black and white tube opposed to the green and white. First time I've seen 502 on the shelf.
Not the first time something like that has happened, as in manf not know what they should know. On our most recent fifth wheel, I was on the phone with the factory asking about tank sizes since the brochure advertised 4, and I had 5. They had the prints, went out on the assembly line while I was on the phone, and still took a shot in the dark. I never knew what they really were, just big.
John and Rebecca Dickson
Emma-8 / Little John-5 / Iva-1+
2013 Ford F-350 Lariat FX4, CC LB PSD, DRW
2015 Jayco Jay Flight 28BHBE (#8)