https://backpack.tf/item/3134248931

https://backpack.tf/profiles/76561198316624014#!/compare/1756339200/1756425600

https://backpack.tf/profiles/76561199582907694#!/compare/1756339200/1756425600

https://stntrading.eu/item/tf2/Wings%20of%20Purity

Technically exact sale to STN is untraceable, but from last suggestion, the buy order on STN has remained unchanged at 6 keys 56.55 ref and has since bought two more Wings, so we could reasonably assume it was bought for that. At the time keys were also 52.72 ref, so we could take this sale as effectively ~7 keys.

https://backpack.tf/item/3172340807

https://backpack.tf/profiles/76561198088837823#!/compare/1756339200/1756425600

https://backpack.tf/profiles/76561198310454087#!/compare/1756339200/1756425600

Same case as above to STN, most likely ~7 keys

https://backpack.tf/item/3136744847

https://backpack.tf/profiles/76561197975508167#!/compare/1752883200/1752969600

https://backpack.tf/profiles/76561198164984732#!/compare/1753228800/1754611200

Older untraceable sale but from seller's side looks like it could potentially be 7 keys

Current 8.1 key unsolds seem to suggest older Marketplace sales may be a bit high so excluding those for now. Taking 7 flat.