That's not the best way to securely ship a cone speaker. Over the years, I sold several Altec and JBL speaker drivers, and a few were shipped to Italy.
A safe way of boxing a pair of woofers is to bolt them together face to face to protect the cones, and use bubble wrap and plastic peanuts to fill the box. When you have only one cone driver to ship, I use an MDF board to screw the driver to and which I place at the bottom of the box, then bubble wrap and plastic peanuts.