I don't have an answer but Bergquist makes similar insulators.
You'll need to measure the uncompressed thickness and whether it has a fiberglass reinforcement layer or not (it doesn't appear to have a Kapton core).
There will be different grades, the most conductive will cost more.
Awesome. Thanks Perry. I'll look into them more. I've been using Kapton to replace them all... but would like to try and get something close to factory.
