NOS Campagnolo Porta-Catena Chain Holder: 2-Bolt Version

This is a rare 1970's and early 1980's dropout chain rest, which was a part of the Campagnolo Nuovo Record Portacatena 1013/6 downtube shifter system.  It's largely a standard friction shifter, but the lever has a flip lever which shifts the derailleur onto the chain holder to make removing the rear wheel easier/quicker.  This was designed for racing situations where changing your wheel quicker than the next rider wins the race.  It's also helpful for general riding and wrenching.

There is a lot of mystery around the Portacatena in the bike world, as it's just kind of wonky.  Helpfully, portacatena translates from Italian to "Chain Holder". 

This is the two bolt version, there's also a one bolt version.  These require special Campagnolo dropouts with holes threaded for these one or two bolts, or just drill and thread your own holes in your dropouts (just be careful to research just where and what size the holes should be)

Condition

New old stock with screws and manual