Sale 2 seems to be the Vexed Volcanics Handsome Handy Thing (priced at 13 keys 2 weeks ago). Neither of the keys seem to match so that sale should be taken as 13 keys.

Here are some more sales:

Item 2: https://backpack.tf/item/16706946394

Sale 4:

https://backpack.tf/profiles/76561198135388328#!/compare/1772582400/1772668800

https://backpack.tf/profiles/76561199220120148#!/compare/1772582400/1773187200

Untrace

Item 3: https://backpack.tf/item/15521660893

Listed on Mannco.Store

Item 4: https://backpack.tf/item/11923756851

Sale 5:

https://backpack.tf/profiles/76561199581722058#!/compare/1768348800/1768435200

https://backpack.tf/profiles/76561199084012819#!/compare/1768435200/1768608000

6 keys match

Item 5: https://backpack.tf/item/9447450643

Sale 6:

https://backpack.tf/profiles/76561199013645470#!/compare/1769558400/1770249600

https://backpack.tf/profiles/76561199110809353#!/compare/1769472000/1769558400

One of the people who bought it off of MPTF in November dumped it to Quicksell.Store

Sale 7:

https://backpack.tf/profiles/76561199110809353#!/compare/1772064000/1772150400

https://backpack.tf/profiles/76561198091502579#!/compare/1772064000/1772150400

Bought in bulk for keys then listed on MPTF

Item 6: https://backpack.tf/item/7957350958

Sale 8:

https://backpack.tf/profiles/76561199074568629#!/compare/1771459200/1773792000

https://backpack.tf/profiles/76561198180923509#!/compare/1772841600/1772928000

Bought on SCM, was either 10 or 11 keys https://imgur.com/9CnDfHA https://imgur.com/e4HqmXr

Under buyers regardless

Buyer listed it on Mannco.Store

MPTF sales: https://marketplace.tf/items/tf2/614;5;u57

Sale 9:

Sold for $39.99 on Jan 17 2026

Keys were $1.82 https://marketplace.tf/items/tf2/5021;6

39.99/1.82=21.97 ~22 keys

Sale 10:

Sold for $39.99 on Feb 18 2026

Keys were $1.84

39.99/1.84=21.73 ~22 keys

Sale 11:

Sold for $39.99 on Feb 22 2026

Keys were $1.88

39.99/1.88=21.27 ~21 keys

The one you provided was $29.99 and not $29.99, so that would make 29.99/1.8=16.66 ~16 keys

That totales sales at:

10/11, 13, 14, 16, 21, 22, 22

Sellers:

BPTF - https://imgur.com/dCMxkNI 15 keys (1 day), 15.55 keys (11 days)

MPTF - https://marketplace.tf/items/tf2/614;5;u57 $39.99 (~21 keys)

STN - https://stntrading.eu/item/tf2/Unusual+Terror-Watt+Hot+Dogger none

SCM - https://steamcommunity.com/market/listings/440/Unusual%20Hot%20Dogger?filter=Terror-Watt https://imgur.com/5IFuZbX 53.82€ (~26 keys)

11 days doesn't seem like enough counter-evidence, however 13-22 feels wide itself. Given we're already excluding a lower sale, you could probably exclude the sales at 21-22 too and go with 13-16 keys