Rubber grommets are a bit past it.
I searched the web for new ones but was unsuccessful so what to use to replace them?
I have for years picked up all sorts of rubber suspension rubbers and the like. So I dug them out and found that I had a few rubbers which I drilled to size inside and then shaped the outside, I then cut them not in half but about 1/3rd of the width which gave me two thick and two thin half grommets. Using the two thick ones, I trimmed them to size and then when I was ready to fit them I glued the two insides together which resulted in an excellent grommet looking from both sides and fully insulating as well.
Rick