The collar has a card with a seal attached to it authenticating it.
There is also a card from a member of the papal household verifying that Pope Leo XIII owned it.
A traditional Roman collar is a stiff narrow band that acts as a white collar fastened at the back of the neck. It is worn by Catholic and some Protestant clergy.
A Roman collar is a distinctive symbol of the clergy.
This collar is not the traditional Roman collar as we know it. Instead it is a fairly large piece of cloth with the basic collar. Additionally there is a cloth coming down over the chest.