Adult Reefhopper Water Shoes, UPF50+. They provide excellent protection from hot sand and rocks, with an upper Neoprene Fabric and rubber sole. Available in several colors. SIZING: How to measure your foot to determine your size: Trace the bottom of your bare foot on a piece of paper, then measure from the heel to the top of your big toe. If your size is in between sizes, choose the larger size. If you need a smaller size, check the kid's water shoes.