Two recent sales on this very nice hat:

https://backpack.tf/profiles/76561198094055063#!/compare/1555113600/1555200000

[Thanks to KFC Jamal for this information]

Sold for $150 on the Community Market (https://i.imgur.com/tsFVEY8.png)

Keys were $2.42 at the time. (https://i.imgur.com/Yj4p43E.png)

150.20/2.42= roughly 62 (62.06)

(62 is the highest key valuation that can be used here, as $150 of wallet funds can only purchase a maximum of 62 keys from the market, regardless of their price on other sites.)

Same hat sold 3rd May, for 80 keys pure

https://backpack.tf/profiles/76561198094055063#!/compare/1556755200/1556841600

Seller's B/O was 80.

Taking 62-80.