https://backpack.tf/item/1648012162 - this history contains all the sales for this item.

Sale 1:

Sold for Purple Energy Brass Bucket (56)

No outpost

Seller: https://backpack.tf/profiles/76561198302774496#!/compare/1528416000/1528588800

Buyer: https://backpack.tf/profiles/76561198095236132#!/compare/1528502400/1528588800

X = 56

Sale 2:

Quicksold for 45 keys

Seller: https://backpack.tf/profiles/76561198002757046#!/compare/1528502400/1528588800

Buyer: https://backpack.tf/profiles/76561198004517334#!/compare/1528502400/1528588800

X = 45

Sale 3:

Most likely sold to a quickbuyer

Seller: https://backpack.tf/profiles/76561198095236132#!/compare/1528502400/1528588800

Buyer: https://backpack.tf/profiles/76561198002757046#!/compare/1528502400/1528588800

Sale 4:

Sold with items for Bonzo Gridiron

Seller: https://backpack.tf/profiles/76561198134407457#!/compare/1528502400/1528588800

Buyer: https://backpack.tf/profiles/76561198302774496#!/compare/1528416000/1528588800

Was used to update the Gridiron

Sellers:

https://i.imgur.com/dS52T38.png

https://backpack.tf/item/1648012162 - 60 keys

Sales at:

45

56

45 quicksold, excluding it.

Going with 56 flat.