Vintage detachable semi-stiff collar by Akco, made around the 1960s.  Polyester/cotton. 
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.

SizeCollar size 16 (to fit shirt size 15.5).

Condition: Vintage collar, made over half a century ago, but never used and in perfect condition.