Thermo-X layering fabrics provide incredible insulation with low bulk and quick-dry properties. Base-Layer Insulation Quick Dry 4-Way Stretch Fabric Strategic Seam Placement Rash Protection Super Low Neck: No Interference with Wetsuit Neck Boardshort Connector Cinch Cord Performance Fit: Form-Fitting Tight Layer Fits Like A Second Skin Thermo-X HyperDry: 220g Nylon/Spandex with HyperDry technology for maximum insulation and minimal water absorption Flatlock Stitched: Breathable Seams | O'Neill Women's Thermo-X Long Sleeves Crew in Black, Size Medium, Nylon/Spandex