Vintage Real Black Leather retailer Ballet Shoes Slippers Ballerina, Made in USA

This is a pair of Vintage black genuine leather ballet slippers.
These have been used but still look very good.
They are real leather with a canvas inner part. The soles are leather too.
I am unsure of their exact age, but they are stamped Made in USA, so I'm thinking definitely earlier than 1980's.

They are marked 5 1/2 C inside the shoes. That is a Woman's U.S. size 5 1/2 and C has something to do with the width. They measure 9 inches from toe to heel.
I wear a size 6 1/2 and I'm modeling them retailer in the photo, they fit pretty good.
You just don't find these in leather very often, especially in black!
They are in very good condition!