C-Skins Swim Research 3mm Neoprene Swim Cap - Unisex\'s A flexible, lightweight neoprene swim cap for open water swimming. The Swim Research 3mm Swim Cap has excellent multi-directional stretch and flexible quick dry thermal lining for great comfort. Keep you head warm during open water swimming this winter! Features: 100% Xtend neoprene: Flexible, lightweight, super hydrophobic external lining that has excellent multi-directional stretch Strata neoprene: Embossing channels in the neoprene on the top of the cap improve the flow of water Mesh Skin: Reduces wind chill and increases warmth Liquid Sealed Seams: Applied to the external seam to enhance waterproofing and strength Hype 3 Catch Palm: Multi-Layer PE ink designed for minimal resistance on your forward stroke and maximum resistance on your catch and pull Glued and Blindstitched Seams (GBS): A watertight method of construction that results in superior warmth and maximum comfort Performance Driven Minimal Panel Design: Strategically positioned seams reduce drag and improve comfort True 3mm Thickness: A warmer thicker product that doesn’t mislead our customers Size Chart Adult Cap Size Circumference XS 51cm  /  20.07in S 53cm  /  20.86in M 56cm  /  22.04in L 58cm  /  22.83in XL 61cm  /  24.01in