The Thule Key 8 is pretty hard to get hold of. This is a genuine item and was used on a Thule Yepp Maxi frame mount kids bike seat.
Thule Key and Barrel 8-pack = 8 Barrels, 2 Keys, 1 Remover Key
Thule Key and Barrel Official Thule dealer 1 Barrel, 1 Key & 1 Remover Key
Thule Key and Barrel, 2 Keys, 1 Barrel 1 Remover Key One-key system 52484
Thule Key and Barrel 4-pack = 4 Barrels, 2 Keys, 1 Remover Key
Thule Key and Barrel 6-pack = 6 Barrels, 2 Keys, 1 Remover Key
Thule Key and Barrel: 3-pack 3 Barrels, 2 Keys, 1 Remover Key