Bikepacking - a viable alternative to racks & panniers

A bit of spanglis to english translation here:

Yes, I sell the adaptor including 4 screws (2 for frame, 2 for bidon cage) and 4 washers (to avoid the band-on derailler, and also the bidon cage if it doesn't have a hole between screws) But washers haven't arrived yet, I expect them this week.

Price is 12,5 £ (including shipping costs to UK)