The Sale:

Sold with parted Strange Enforcer (<0.5) for Strange Spec. KS Gunslinger (18) + Strange Spec. KS Kritzkrieg (12.5)

http://www.tf2outpost.com/trade/28504734 - B/O of 30

Seller: http://backpack.tf/profiles/76561198074789287#!/compare/1475280000/1475366400

Buyer: http://backpack.tf/profiles/76561198011448525#!/compare/1475366400/1475452800

X = 30 (Capped by B/O)

Sellers:

29 keys:

http://i.imgur.com/nDNIvZu.png - young, most likely re-listed

http://backpack.tf/u/76561198046160451

30 keys:

http://i.imgur.com/yYF4RzU.png - 3 days

http://www.tf2outpost.com/trade/28577289

http://backpack.tf/u/76561198055847835

35 keys:

http://www.tf2outpost.com/trade/28531251 - 3 weeks (probably relisted a few times, seller owns two)

http://backpack.tf/u/76561198054758757

36 keys:

http://i.imgur.com/O8po3rV.png - 4 months

http://backpack.tf/u/76561198061376237

80 keys:

http://i.imgur.com/w0y2UEZ.png - 3 days

http://backpack.tf/u/76561198119563409

Sales at:

30

Seller at 29

Going with 29-30