You have a pair of Mares Razor Fins, and need to replace your foot pockets or are a seasoned free diver who knows one can never have enough spare items in their save-a-dive-kit to be properly prepared for any contingency. Razor foot pockets are designed to be worn with a 3mm neoprene sock. If you are wearing these fins barefoot, use the next size smaller fins. The foot pocket is incredibly comfortable due to the design developed in collaboration with a leading Italian foot (podology) clinic. Its shapes and the extra thickness on the instep and the tensioners under the arch have been meticulously researched to convey the maximum amount of energy produced to the blade, yet still provide complete comfort. Foot Pocket is made from rubber and techno-polymer and is designed to be use with the Mares SKU: MRSFRF Razor Pro and SKU: MRSFRC Razor-Carbon has a large heel pull tab for easy donning and doffing, Foot pocket comes in multiple sizes.