Sale 1:

Sold for 24 keys

Seller: https://backpack.tf/profiles/76561198084367252#!/compare/1556928000/1557014400

Buyer: https://backpack.tf/profiles/76561198109998059#!/compare/1556928000/1557014400

https://backpack.tf/item/1322762624

X = 24

Sale 2:

Sold with a key for Well-Worn Isotope Leopard Printed Pistol (22.5)

Seller: https://backpack.tf/profiles/76561198294426922#!/compare/1555804800/1555891200

Buyer: https://backpack.tf/profiles/76561198071230830#!/compare/1555804800/1555891200

https://backpack.tf/item/809390562

X = 22

Sale 3:

Sold for 21 keys + 23 ref

Seller: https://backpack.tf/profiles/76561198067699902#!/compare/1555718400/1555804800

Buyer: https://backpack.tf/profiles/76561198294426922#!/compare/1555718400/1555804800

X = 21

Sale 4:

Sold for 20 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1560124800/1560211200

Buyer: https://backpack.tf/profiles/76561198044130442#!/compare/1560124800/1560211200

https://backpack.tf/item/1322762624

X = 20

Sale 5:

Sold for Searing Magistrate’s Mullet + 8 keys

Seller: https://backpack.tf/profiles/76561198071230830#!/compare/1555891200/1557360000

Buyer: https://backpack.tf/profiles/76561198090147535#!/compare/1557273600/1557360000

https://backpack.tf/item/809390562

Should fit into the range.

Other Sales:

https://backpack.tf/item/1322762624 (#1 & #2)

https://backpack.tf/item/809390562 (#3 & #4)

https://backpack.tf/item/1473198240 - tradeit

#1

Bulk for Searing Hong Kong Cone

https://backpack.tf/profiles/76561198109998059#!/compare/1557446400/1557878400

https://backpack.tf/profiles/76561198150729025#!/compare/1557792000/1557878400

#2

Sold with 10 keys for Disco Beat Down Universal Translator

https://backpack.tf/profiles/76561198150729025#!/compare/1557964800/1558051200

https://backpack.tf/profiles/76561198148446823#!/compare/1557964800/1558051200

Using on the UT.

#3

Untraceable, sold to a quickbuyer

https://backpack.tf/profiles/76561198148446823#!/compare/1559692800/1559865600

https://backpack.tf/profiles/76561198337734785#!/compare/1559779200/1559865600

#4

Untraceable, only some keys match

https://backpack.tf/profiles/76561198802991149#!/compare/1555718400/1555804800

https://backpack.tf/profiles/76561198067699902#!/compare/1555718400/1555804800

Sellers:

https://i.imgur.com/lPjskZZ.png

https://backpack.tf/item/1322762624 - 26 keys

https://backpack.tf/item/809390562 - 40 keys

Sales at:

20

21

22

24

Taking 20-24.