Probably the most iconic (and most knocked-off) chair to have ever existed, the Barcelona Chair. 

This authentic Knoll chair is in excellent condition with very little signs of use,  I mean check the photos! It looks better than any gently used Barcelona I've seen available. 

The polished chrome frames show no seams or signs of abuse. In fact, the only thing on the frames worth noting is that they all have the official Knoll stamp on them so you can be assured they are true Barcelona chairs and not one of the mass produced replicas many try to pass off as authentic. 

The leather is a a soft, supple black top grain leather with Knoll label still attached to the seat cushion.

The chairs leather straps are in excellent condition with no noticeable signs of splitting, cracking, or stretching as can be typical with heavily worn Barcelona chairs. 

This exact same set up would run you $6,700 (after tax and shipping) if you wanted to buy it new directly from Knoll or DWR.

I can confidently say you wont find a better value (price for condition) in regards to an authentic Barcelona chair anywhere in the country.