I just brought this hat for 35 keys

Proof:

http://puu.sh/phu3Q/5e0d3225a1.png

http://backpack.tf/profiles/76561198018101085#!/compare/1464998400/1465084800

However I can't find any other history for it. It was listed on Bazaar about a year ago and never sold

http://bazaar.tf/trade/905957

And then it was sold on March 22nd 2016

https://backpack.tf/profiles/76561198061224177?time=1458630000

But I can not work out for what because the history jumps 3 days and the user seems to have cleared everything of value from his backpack.

This might not be enough proof and maybe I'm just being stupid because I can't figure out what the previous trades were for, but this is all I've got and I don't think anyone else is going to try and price this thing any time soon.