Vintage detachable stiff shirt collar, in very good condition.   This is an American Arrow collar from Cluett, Peabody & Co.  Roll front "Duncan" style.  Probably made around 1900-1920.
You will need a pair of collar studs. These are NOT included with the item, but are available separately.
Size:   Collar size 15.5 (to fit 15" shirt)

Condition:  
Vintage collar, around a century old and in very good condition.  It has been laundered and starched since it was last used, and apart from very slight fading as shown in the close-up photograph, it is in near-perfect condition.
 Marked with previous owner's name, and 5/1/1, which may be a date.