WTB: Nauticam N120 20mm extension ring

I'm looking for a 20mm ring for use with the 8.5" dome / Sigma 15 + TC1.4.

If you're still looking, I have one I'm willing to sell. It's the Nauticam Extension Ring 20mm w/ lock.

Is in very good condition. I purchased it with a 30mm extension, but have never used the 20mm myself.

Send me PM or reply to this thread.

Closing this out; I acquired a 20mm ring recently.