There seem to be two types of heating elements that have been used in RM-100s - the cartridge type and the pencil type. The cartridge type, according to pplmotorhomes, in no longer available.
I ordered the pencil type, and it was correct for my 1979 model. The part number there is
and I paid $44.84 for it. I had to get them to match it up by wattage, so maybe this will save you a little time.
1975 Argosy 28 "Argosy"
1979 Excella 500 31 "Betsy"
1992 Lincoln Mk 7 LSC
2003 Dodge 2500 Cummins "TowHog"
"Lucy Loosehair" the cat - Airstream mascot
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