These are photos of the headphones that I use in my ham shack. As you can see, the dark gray foam rubber inside is deteriorating, and I need to replace it. It appears to be open-cell foam "rubber" between 1/8" and 3/16" thick.
One of the headphones has had little use (bought it as a spare) and shows the original size of the hole centered around the element's sound holes.
They are military surplus communications phones with just the right frequency response for SSB ham radio use.
That foam is holding the elements in place. Notice that one element where there is almost no foam left is loose. However, it is not particularly stiff. That may or may not be because it is so deteriorated.
Does it matter what kind of foam is needed to replace this deteriorating stuff? Regardless, where can I get it? (It doesn't matter what color it is.)