This is a repair kit for your Studer Revox NAB adapters.  They are new.  Free shipping in the US. 

The photo with the red background shows what you will receive.  The other photo shows the type of NAB hubs that these fit, but the listing is for the two o-rings and six small reel clamping discs only. 

THIS LISTING DOES NOT INCLUDE THE FIVE COMPLETE REEL ADAPTER HUBS, THEY ARE SHOWN SO YOU KNOW WHAT THIS REPAIR KIT FITS. 

SEE THE PHOTO WITH THE RED BACKGROUND TO KNOW WHAT IS INCLUDED.  It fits Studer/Revox hubs with or without the aluminum knob.

If your rubber o-rings broke, chances are you may have lost some of the little plastic discs which help squeeze the rubber uniformly to hold the reel.  Each hub has three, and this kit contains the 2 rubber o-rings and 6 nylon washers that are the same size as the original plastic discs.  Together they restore old hubs to perfect working order, and can be installed with no tools. 

Instructions: The discs are placed in their recesses and the o-ring is stretched around the hub and into the slot in the hub.  The o-ring will keep the discs in place.  Do not take the hub apart. It is analogous to putting a rubber band on your wrist, you do not need to remove your hand to do this. :)  Remove the old o-ring, you can cut it if you can't pry it out, but a blunt knife like a butter knife usually helps pry it out. If you have the three discs, you won't need the ones I sent.  Of course if your old o-ring broke, you may have lost the 3 discs. Place them in their three slots around the sides of the hub and stretch the o-ring around the entire hub and snap it into place. The o-ring is all that holds the three discs in place so make sure they don't fall out while you are stretching the o-ring into its slot.

You will receive the two O-rings and six discs in a regular white business envelope.  Be sure to be looking for it in the mail.