Vintage detachable plasticised shirt collar.
Pearline brand, early 20th century.
It is marked:
1 1/2 x 14
METAL INSERTION BUTTONHOLES
This collar is stiff.
It appears to be made (or coated) with some sort of plastic.
It is a wipe-clean (not washable) material, similar to the sort of material sometimes used for clerical collars.
The "metal insertion buttonholes" are discs of metal inside the collar, presumably to stop the stud holes from becoming damaged.
You will need a pair of collar studs to fix this collar to your tunic shirt.
These are NOT included, but are available from my other listings.
The stud in the photographs is just for display purposes.
Size Collar size 14 inches
Depth one-and-a-half inches
These collars were made about a century ago.
Although they have never been worn, they do have a few tiny spots from storage, as shown.
In view of their age, I think these are unlikely to come out.