hehe, I'ld expect it to be a bit more than 100 simply b/c its a event robe with a resist, in fact the only that I can think of atm with poison, and since it exists in single digits(could've been duped, who knows) and poison has become a much more necessary resist I'ld expect it to go for around 200m.
Also if you want to see one there was one displayed in a museum on Pacific in Luna, on the south side of town. If I remember correctly the house is along the inner wall one or two houses east of the south gate.