http://www.tf2outpost.com/trade/8366148 - Offered 4 pure, owner considers it notable.

http://www.tf2outpost.com/trade/9049818 - Sold for a Knifestorm Bombing Run, an Orbiting Fire Sober Stuntman and a Hearts Mongolian (~3.6 with overpay) - backpack of the guy he traded with is here: http://www.tf2outpost.com/backpack/186702

and the Bombing Run is here:

http://www.tf2outpost.com/trade/8988357

The item histories match.

http://www.tf2outpost.com/trade/6938797 - Undefined sale. C/O'ed ~3.6 in unusuals, considered 3.5 pure a bit low.

Verdict: Low end for one offer and one sale was ~3.6 buds, high end is currently 4. Not unrealistic to think the hat could close for nine more keys.

Please tell me what you think, counterproof is appreciated.