Ally Floating Swim Fins Size Chart: Small 5-6.5 Medium 7-8.5 Medium/Large 9-10.5 Large 11-12.5 Extra Large 13.5-14.5 Made of the finest quality natural rubber designed for body boarding and bodysurfing Its soft foot pocket with stiff blade offers increased acceleration and super fast take offs making it easier to catch waves A bat tail like blade with two rods for maximum thrust and power Traction bottom with breather hold at the bottom of the foot pocket for proper drainage which allows sand and broken shells to circulate out