Detachable semi-stiff "Prince" shirt collar, of traditional design, by Gieves & Hawkes (the naval outfitters of Savile Row).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 1970s or 1980s.
The collar can be starched if preferred, but this is not necessary.
Collar size 16 inches.