is this derailleur short cage or long cage? I'm selling the rear derailleur off this bike, and someone asked whether it's short or long cage. I assume it's long. Is this correct?
Campagnolo derailleurs come in three lengths, short, medium and large.

To determine the size measure it. The centre to centre distance between the sprockets is 55, 72.5 and 89 mm and my guess is that you have a medium flavour rear derailleur...

How much are you selling it for, b.t.w.?