Sale 1:

https://backpack.tf/profiles/76561198052736868#!/compare/1581465600/1581552000

https://backpack.tf/profiles/76561198121171343#!/compare/1581465600/1581552000

Sold for Max Head(~19)

https://bot.tf/stats/listings/4ZK6ZEV0

B/O of 19 keys

sale 2:

https://backpack.tf/profiles/76561198121171343#!/compare/1581465600/1581552000

https://backpack.tf/profiles/76561198002757046#!/compare/1581465600/1581552000

Bulky

sale 3:

https://backpack.tf/profiles/76561198002757046#!/compare/1581724800/1581811200

https://backpack.tf/profiles/76561198351473049#!/compare/1581379200/1581811200

Sold for 16 keys

sale 4:

https://backpack.tf/profiles/76561198351473049#!/compare/1581811200/1581897600

https://backpack.tf/profiles/76561198337734785#!/compare/1581811200/1581897600

QS for ~12 keys a day after Sale 3

Sale 5:

https://backpack.tf/profiles/76561198337734785#!/compare/1582156800/1582243200

https://backpack.tf/profiles/76561198188401374#!/compare/1581984000/1582243200

Sold for keys

sale 6:

https://backpack.tf/profiles/76561198188401374#!/compare/1583366400/1583625600

https://backpack.tf/profiles/76561198434300489#!/compare/1583539200/1583625600

Sold for DBD Fuku + negligible sweets

use there

https://bot.tf/stats/listings/46N5Q7K0

B/O of 19 keys

sale 7:

https://backpack.tf/profiles/76561198434300489#!/compare/1583539200/1583625600

https://backpack.tf/profiles/76561198333986358#!/compare/1583539200/1583625600

Untrace

sale 8:

https://backpack.tf/profiles/76561198196894698#!/compare/1587081600/1587168000

https://backpack.tf/profiles/76561198388105049#!/compare/1587168000/1587340800

Untrace

sale 9:

https://backpack.tf/profiles/76561198388105049#!/compare/1587168000/1587340800

https://backpack.tf/profiles/76561198131081286#!/compare/1587254400/1587427200

Sold for Blizzardy Barnstormer

use there

sale 10:

https://marketplace.tf/items/tf2/137;5;u30

$34 / $1.77 = 19.21 keys

Total sales @:

12, 16, 19, 19 keys

buyers up to 15 keys,

sellers down to 20 keys,

considering 16 resold for lower,

taking 16 - 19 keys