Detachable starched day collar by Hackett of London. 100% cotton, made in England.  The style is called "Cameron".  

Measurement straight down from top to the point is just under 2.5".  Depth at the back is 1.75". 

You will need a pair of collar studs to fix this collar to your tunic shirt.  These studs are available separately (the stud in the pictures is just for display).

Size: Collar size 15 (to fit shirt size 14.5)

Condition: Men's collar, several years old, in good used condition.  Has been professionally laundered and starched since it was last used.  Previous owner's laundry mark on the inside.