Always happy to contribute to delinquency...at least of the radio variety.
Probably the most comfortable and good sounding earphones I ever used were a set of WWII surplus with the large rubber cushions that looked like a giant suction cup. One of the CW guys had them at Field Day years ago. Never had any luck finding a set, though I saw Fair was selling the cushions for $25 a while back.
Possibly the Harvard Design 8-C "dual seal" cushion, a combination of the circumaural and supra-aural designs. I don't have a ready reference for the JAN designation, but like you, I have seen them occasionally at hamfests.
The other smaller, more solid rubber cushions look more like a toilet plunger and though the phones sound good, comfort goes away fairly fast. They press against the ear and don't seal.
MC-162-A. I think these are the most familiar to hams, since they were usually supplied with surplus earphones after the war. They are profoundly uncomfortable because of the rubber hardness, and don't do a very good job of excluding outside noise, either. I guess that's one of the reasons they were dumped by the millions on poor unsuspecting radio amateurs who may have thought they were getting "authentic" aircraft headphone assemblies. Well, to be fair, they were getting them, I suppose - the cushions were just obsolete.
Those chamois cushions are nice and seal around the ear well. I've got a couple sets of those with the pic attached ala 'Strategic Air Command' with Jimmy Stewart. They also work fine.
These NAF-48490-1 cushions seem to be the most common on the 'bay, probably because they became the Joint choice for quite a few years.
