I finally was able to borrow an n100 extension ring to get measurements and make prototypes of Nauticam n100 compatible parts. I can print out any size ring from 20mm on up.

It all fits perfectly, but still needs to be tested in a vacuum sealed housing followed by a test dive. The basic design pattern and pressure resistance is well tested in the n120 versions I've been using for months.

The person I borrowed the ring from is out of town for a few weeks, and I don't have a housing to test it,

I need to find someone else to test it out. Any volunteers??

If you want to send it to me, I can easily test it to the 100m that the Nauticam stuff is rated to.