You will receive 10 croc charm backings total, each measuring 10mm on the insert with the head attachment measuring 12mm round. They have been tested and proven for quality. These are not a floppy rubber insert, and are actually a stiff, hard, and durable material. Can be used for rubber charms with no backing or 2cm acrylic pieces. Truly wahtever you can think of to attach to them! Can be used for more then just shoes.