Resuggestion, thanks to Xergoyf

https://backpack.tf/item/5009501250

Sold for 5 keys pure:

https://backpack.tf/profiles/76561198002757046#!/compare/1600732800/1600819200

https://backpack.tf/profiles/76561198101793900#!/compare/1600732800/1600905600

Classified to prove it: https://bot.tf/stats/listings/4P0NW5O5

5 keys 21 ref pure, 5.45 keys ~5.5:

https://backpack.tf/item/8233809166

https://backpack.tf/profiles/76561198190567127#!/compare/1603152000/1603238400

https://backpack.tf/profiles/76561198113800058#!/compare/1603238400/1603324800

Marketplace.tf sale untraceable via compare links: https://marketplace.tf/items/tf2/1119;5;u3027

July 23 2020: $12.99/1.92=6.77 keys ~7

Seller at 5 keys was listed at 4 keys 20 ref since May 5th https://bot.tf/stats/listings/Y80W0Q9Z

They listed at 5 keys on August 21 then it took about a month to sell https://bot.tf/stats/listings/4O9NX92Q

I think we can call 7 keys high here. Going with 5-5.5 keys