Sale 1:

Sold for Spec. KS Aus Wrench (~32) + Spec. KS Aus Frontier Justice (~10)

Seller: https://backpack.tf/profiles/76561198200449097#!/compare/1538524800/1547078400

Buyer: https://backpack.tf/profiles/76561198119662522#!/compare/1546992000/1547078400

https://backpack.tf/item/6809518285

Frontier Sold for 10 in the seller’s end. Taking 10.

X = 42

Sale 2:

Sold for 34 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1547683200/1547769600

Buyer: https://backpack.tf/profiles/76561198236463682#!/compare/1530144000/1547769600

https://backpack.tf/item/6817825708

X = 34

Sale 3:

Sold for 34 keys

Seller: https://backpack.tf/profiles/76561198312583107#!/compare/1553817600/1553904000

Buyer: https://backpack.tf/profiles/76561198137148352#!/compare/1552608000/1553904000

https://backpack.tf/item/6672655582

X = 34

Sale 4:

Quicksold for 33 keys

Seller: https://backpack.tf/profiles/76561198179707937#!/compare/1547337600/1547424000

Buyer: https://backpack.tf/profiles/76561198133887117#!/compare/1547337600/1547424000

https://backpack.tf/item/6809518285

X = 33

Sale 5:

Sold for 33 keys

Seller: https://backpack.tf/profiles/76561198125791160#!/compare/1552953600/1553040000

Buyer: https://backpack.tf/profiles/76561198309832044#!/compare/1552867200/1552953600

https://backpack.tf/item/3532419751

X = 33

Sale 6:

Sold with less than half a key in metal for 32 keys

Seller: https://backpack.tf/profiles/76561198323565601#!/compare/1551744000/1551830400

Buyer: https://backpack.tf/profiles/76561198087511120#!/compare/1551398400/1551830400

https://backpack.tf/item/6809518285

https://i.imgur.com/FQVRuSh.png - B/O of ~31.5

X = 32

Sale 7:

Sold to a quickbuyer for 31 keys

Seller: https://backpack.tf/profiles/76561198087511120#!/compare/1554336000/1554595200

Buyer: https://backpack.tf/profiles/76561198342161127#!/compare/1554508800/1554595200

https://backpack.tf/item/6809518285

X = 31

Sale 8:

Sold for 21 keys + Blizzardy Brain-Warming Wear

Seller: https://backpack.tf/profiles/76561198133887117#!/compare/1550793600/1551052800

BUyer: https://backpack.tf/profiles/76561198148843171#!/compare/1550966400/1551052800

https://backpack.tf/item/6809518285

Will fit into the range.

Marketplace Sales:

https://marketplace.tf/items/30066;5;u6

https://manic.tf/keyprice/?at=2019-04-02 - $69.99 / $1.79 = 39.10 keys

$44.02 went to a buy order, excluding.

X = 39

Other Sales:

https://backpack.tf/item/7606708597 (#1)

https://backpack.tf/item/6817825708 (#2)

https://backpack.tf/item/6809518285 (#3-5)

https://backpack.tf/item/6145416567 (#6)

https://backpack.tf/item/7149968813 - marketplace

https://backpack.tf/item/3405484447 - gambled

#1

Untraceable

https://backpack.tf/profiles/76561198395757940#!/compare/1551916800/1552003200

https://backpack.tf/profiles/76561198312583107#!/compare/1551744000/1551916800

Not even listed on bot.tf, so it may have been an item sale.

#2

Untraceable

https://backpack.tf/profiles/76561198236463682#!/compare/1548460800/1548547200

https://backpack.tf/profiles/76561198114402400#!/compare/1548460800/1548547200

may have gone to a buy order

#3

Sold with 15 keys for Vivid Plasma Mining Light

https://backpack.tf/profiles/76561198119662522#!/compare/1547164800/1547251200

https://backpack.tf/profiles/76561198077827191#!/compare/1546905600/1547251200

Can be used on the light.

#4

Sold for 31 keys to a quickbuyer?

https://backpack.tf/profiles/76561198077827191#!/compare/1547251200/1547337600

https://backpack.tf/profiles/76561198179707937#!/compare/1547251200/1547337600

#5

Untraceable

https://backpack.tf/profiles/76561198148843171#!/compare/1551571200/1551657600

https://backpack.tf/profiles/76561198323565601#!/compare/1551571200/1551657600

#6

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1546992000/1547078400

https://backpack.tf/profiles/76561198171409190#!/compare/1546992000/1547078400

#7

Bulk for pure

https://backpack.tf/profiles/76561198058223674#!/compare/1544832000/1548979200

https://backpack.tf/profiles/76561198125791160#!/compare/1548892800/1548979200

Sellers:

https://i.imgur.com/h0ua2iq.png

https://backpack.tf/item/7606708597 - 34 keys

https://backpack.tf/item/6181967389 - 45 keys

Sales at:

31

32

33 (2x)

34 (2x)

39

42

Seller at 34, and the sales at 39 & 42 already look like an outlier anyways. Excluding 39 and 42.

31 may have gone to a quickbuyer, but given how close it is to other sales, and the lack of current visible buyers at 31, it should be fine to keep.

Going with 31-34.