I worked on a lot of European cars BITD - Fiats, Peugeots, Citroens, etc. - and they all had those sizes, except maybe the 12, only very old Citroens used that.
5mm bolt = 8mm wrench, 6 = 10, 8 = 13, 10 = 17. On Citroens, 7mm = 11 or 12.
Last edited by Reynolds; 08-18-25 at 02:45 PM.