Vintage detachable Rocola wing collar, made in England, probably in the first part of the 20th century.  This is a classic starched collar, for formal wear.  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.  (The stud in the photographs is just for display purposes).

Collar size......14.5 inches (to fit shirt size 14).
Height 2.25 inches.  This is a TALL collar, and if you are not used to wearing stiff collars, you will probably find it uncomfortable at first.

Condition: 
Vintage collar, many decades old, but unused and in superb condition.