What's a "respiff"?
Factory refurbished. The unit was returned from the distribution channel and has been examined by the factory. It was repaired if necessary and is then put back into the market as what is called "B Stock". The warranty is generally shorter, but some will argue that the unit is more reliable because it has gone through full testing instead of the random sample testing that A units get.
Others will argue it is less reliable because it already had a problem. That may be true for something like a 606 that is currently in production, but units get returned for a lot of reasons. For example, stock that gets returned when a store goes bankrupt or stops carrying a brand will get put into B stock/refurbished. When a model gets replac3ed, all of the factory overstock will go into the same pool. I have seen estimates that less than 30% of all refurbished units ever had a problem.