They were unsold shop stock, and have been in storage at the shop ever since.
These socks are marked in traditional 1950s-style sock sizes (based on the length of the foot in inches).
They are marked as size 8 1/2 to 9 inches
This is equivalent to UK shoe size 2 1/2 to 4 (ladies' sizes).
Please remember that these are very old socks, and they need to be treated more carefully than modern ones.
These socks are half a century old, and if you wish to wear them, they will need to be hand-washed first.