Black Velvet and Lace Knee High Heeled Zipper Boot

This interesting pair of black knee high velvet lace boots was given to me by a friend, but they are a bit too big so I hope someone else could fit into them. They are made of a short velvet like material. They have only been worn once Care: The sizing is a bit weird. The bottom of he boot says it’s a 43, but that, if In European size, would make it a US 13, which it’s not. I have estimated that it is a size 9-10. I have based this off of my foot, which is a 8. I have about an inch of toes room.