History 1 (Pro KS): https://backpack.tf/item/3904284418

Duped so not using because clean ones sold recently

History 2 (Pro KS): https://backpack.tf/item/3903571721

Untraceable sale

https://backpack.tf/profiles/76561198084126218#!/compare/1601078400/1601164800

https://backpack.tf/profiles/76561198207987376#!/compare/1601078400/1601251200

History 3 (Pro KS): https://backpack.tf/item/3903486646

Appears as a Marketplace.tf sale https://marketplace.tf/items/tf2/211;0;strange;kt-3

No logged sales

History 4 (pro KS): https://backpack.tf/item/3903350782

Appears as a Marketplace.tf sale https://marketplace.tf/items/tf2/211;0;strange;kt-3

No logged sales

History 5 (Festivized): https://backpack.tf/item/3903079312

Untraceable sale

https://backpack.tf/profiles/76561197965075581#!/compare/1599609600/1600214400

https://backpack.tf/profiles/76561198232041512#!/compare/1599609600/1599696000

Additional Marketplace.tf sales untraceable via item histories

No KS: https://marketplace.tf/items/tf2/211;0;strange

August 30 2020: $260/1.88=138.30 keys ~138

September 24 2020: $400/1.84=217.39 keys ~217

Festivized: https://marketplace.tf/items/tf2/211;0;strange;festive

September 14 2020: $320/1.85=172.97 keys ~173

Excluding 138 because it seems like a low outlier

Going with 173-217 keys, rounding to 175-215 for the sake of everyone's eyes