[Proof below] The Disco Beat Down Industrial Festivizer is a 1 of 1 unusual and I have been able to track down both sales of the hat so far.

Okay now dis is aboot to get a little bit complicated but bear with me. :3

Also I have accounted for unusual and item overpay (Strange Festive Wrench) by multiplying the middle price by 0.90, this gives 10% overpay.

Sales!

1) http://www.tf2outpost.com/trade/12754590

- Sold for the C/O of Green Black Hole Industrial Festivizer + Steaming Old Guadalajara + Strange Festive Wrench.

So...

Green Black Hole Industrial Festivizer: 2.3 x 0.90 = 2.1

Steaming Old Guadalajara: 19 x 0.90 = 17

Strange Festive Wrench: 20 x 0.90 = 18

Added all items together: 2.1 + 0.8 + 0.8 = 3.7 buds

- Proof all these items entered the users backpack: http://i.imgur.com/v5BLMRx.png

- Proof he received the hat: http://i.imgur.com/ovYVnvo.png

2) http://www.tf2outpost.com/trade/12969887

- Sold for Flaming Lantern Vintage Merryweather

So...

Flaming Lantern Vintage Merryweather: 4.1 x 0.90 = 3.7 buds

- Proof of him receiving Flaming Lantern Vintage Merryweather: http://i.imgur.com/pqDRLUl.png

- Proof of him receiving the The Disco Beat Down Industrial Festivizer: http://i.imgur.com/acZiyII.png

I calculated overpay for the wrench because it is classed as slow selling item. That is all the proof I could gather and that I feel is necessary. Any feedback is appreciated. Happy trails! :D