The Nikon PB-6E is a bellows extension for use with the Nikon PB-6 bellows (sold separately), providing a total marked extension of up to 435mm. This extension does not do anything on its own: it needs to be used together with a PB-6 bellows or nothing useful will happen. But if you have a PB-6 and you need extra extension, here's the ticket. Uncommon and in near-new condition, which is a pretty good combination, I think. Includes box.