Yes, they are rare, less then 20 pieces are known till now. Inside works always a Valjoux 23.
Follow our post and roll call about the Nivada Yachtings for further informations HERE!
About the Nivada Book named Chronomaster Only: you can order the book in english end of november on amazon!
https://www.amazon.de/Chronomaster-Only-Gregoire-Rossier/dp/2940506256
or for more info follow the authors on Instagram here: https://www.instagram.com/watchbooksonly/
Seems another well researched book from the authors of Moonwatch Only and can´t wait to read it.
Thanks so much to Anthony, one of the authors, for sending us the wonderful pic for showing here!