Vintage detachable collar, Wyanar Brand (a trademark of Young and Rochester), City style.  Early 20th century (probably late Edwardian/1910s).  Depth 1.25 inches, which is a narrow style.   

 Irish manufacture.

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.

Size: Collar size 16 (to fit shirt size 15.5). 

Condition: Vintage collar, around a century old, but never used and in fairly good condition, but with some storage marks and scuffs.  These collars might be OK for re-enactment/costume use, or for historical interest/display, but  are not suitable to wear formally.