Vintage detachable semi-stiff shirt collar.
This is a Radiac "Kingswear" collar, style number 51.
It is marked Tricoline Faced Collar, British Manufacture.
(Tricoline was a popular fabric from the 1920s to the 1950s, due to its silky texture.)
Suitable for men or women.
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.
Probably made in the 1920s or 1930s.