The Silvestri #3575 Extension Ring #2 is used with their Bicam II camera, and mounts between the Bicam II body and the rear viewing/imaging devices. It is necessary because the Bicam II is so thin, and with some lenses this 30mm of additional path length allows the full focus range.
For use with Bicam II
Offers 30mm of additional extension for proper focus with certain lenses
Made in Italy