Puffy.

Sold for a Magnetic Hat Protector Universal Translator(18 Keys) and ~1 Key in Sweets(19 Keys total)

http://backpack.tf/profiles/76561198071829822/#!/compare/1457938800/1458025200

Sold for an Orbiting Planets Armored Authority(22 Keys) and 1 Key)(23 Keys total)(B/O was 21)

http://backpack.tf/profiles/76561198211717085/#!/compare/1459296000/1459382400

http://www.tf2outpost.com/trade/28007144

Added 1 Key for a Purple Confetti Armored Authority(19.5 Keys, rounding to 20)(19 Keys total)

http://backpack.tf/profiles/76561198090333074/#!/compare/1459468800/1459555200

Sold for a Circling TF Logo Napper's Respite(20 Keys)

http://backpack.tf/profiles/76561198127850098/#!/compare/1459555200/1459641600

http://backpack.tf/item/3012054516

Sales seem to fit, 19-21 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.