<I'm looking for a ring to keep aperture pre-selection with a full manual bellow.> The Nikon BR-6 is designed to be used with their dual cable release for full aperture operation with lens reverse rings or bellows. If you can find a used (now discontinued BR-4) it may do the trick too. The AR-7 cable release should do the trick. regards, Henry Posner/B&H Photo-Video http://www.bhphotovideo.com We will be closed March 31 - April 8, 1999. Please plan accordingly.