Vintage detachable semi-stiff collar.
You will need a pair of collar studs to fix this collar to your tunic shirt.  These studs are NOT included, but are available separately. 
Vintage day collar.  Alistair.

SIZE 16 inches

Condition: Unused but SHOP SOILED.   Collar has some faint marks from storage, and would need to be washed before use (though it might be OK as it is for casual or vintage/costume/re-enactment use or similar).