Vintage Collars Ltd detachable collar.   Style 10a.  
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 pictures is just for display).

Size: Collar size 14 1/2 (to fit shirt size 14).

Condition: Vintage collar, several decades old.  It has been professionally cleaned and starched since it was last used, and is in very good condition.  Previous owner's laundry stamp inside the collar.