It is regular 1inch hex wire, aka, poultry wire, that has been PVC coated.  I found it through hogslatt, since the only thing I could find around here was the galvanized and I am lucky if that last a year.  They had it for the same price as galvanized and I took advantage of their free shipping offer and bought three rolls.  The first two went to making my pheasant/peafowl pens and the last roll was saved for this.  It seems to be much stronger than regular poultry wire, I have never had anything break through it, but I have had raccoons pull quail right through it.  The only problem is that I need more but I cannot afford to ship it, so I will have to figure something out.