History 1: https://backpack.tf/item/8236680751

19 keys + ~1 key of Refined, =20 keys:

https://backpack.tf/profiles/76561198396499936#!/compare/1620518400/1620604800

https://backpack.tf/profiles/76561198137712048#!/compare/1620432000/1620604800

History 2: https://backpack.tf/item/8236384675

Sold on Mannco.Store: https://mannco.store/item/32317

March 27: $40/1.96=20.41 ~20 keys

History 3: https://backpack.tf/item/8163086692

15 keys match in buyer's compare, one of them went to the ref pure:

https://backpack.tf/profiles/76561198163155444#!/compare/1616544000/1616630400

https://backpack.tf/profiles/76561198068367916#!/compare/1616544000/1616630400

Untraceable:

https://backpack.tf/profiles/76561198068367916#!/compare/1616803200/1616889600

https://backpack.tf/profiles/76561198169458269#!/compare/1616803200/1616889600

13 keys + some ref + 2 skins (most likely sold to a buy order):

https://backpack.tf/profiles/76561198169458269#!/compare/1616803200/1616889600

https://backpack.tf/profiles/76561198142788097#!/compare/1616630400/1616889600

https://imgur.com/pSPSdUB

Listed on Mannco.Store at $40 (~22 keys)

Sales at 15, 20, 20. Taking 15-20 keys here

Gladiator.tf was down when I made the suggestion, but the Mannco.Store sale didn't have a buyout.

However for some reason there's a seller at 20 who has been there for 9 months (https://backpack.tf/item/8212262723). I still think 20 as the high end will be fine since there's 2 sales at that value