Monofin Adjustable Mermaid tails Swim Fins with 3 Color for Swimming with Flipper Diving Fins-Girls,Boys(Green)1. It fits children 6-12 years old with youth shoe sizes US 2-7 / EU 24-37. 2. The safety buckle has been fixed before shipment, if you receive the goods, the safety buckle loses, be sure to fix the safety buckle before using. Using the p..