ORIGINAL: aspeed
I just measured it with a vernier and it is kind of oval. It is .015'' to .020''. It says it is good to a motor up to .51 cu. in. I never tried it yet.
I know several people who have tried it once none who have tried it twice! I can't believe they still sell this
stuff .. they can't have sold very many sets EVER, much less enough to justify continuing it.