Sharkskin Chillproof is an aquatic specific, windproof 3-layer composite material with the thermal properties of a 2.5 to 3 mm neoprene wetsuit that will keep you cool when it's hot and warm when it's cold - in, on and under the water. It's neutrally buoyant, flexible and super comfortable. Sharkskin's outer layer is a robust, high quality 4 way stretch material with a durable waterproof coating. The second layer is a 10,000 plus technical membrane that stops windchill and "breathes" to prevent overheating. The 'next to skin' layer is a high tech hollow fibre fleece that retains water when submerged and wicks moisture away on the surface to dry quickly and keep you comfortable. How does it work? When submerged the hollow fibre fleece is designed to absorb and hold water and prevent water flushing through the suit. Your body heats the water which provides a barrier against the cold water outside of the suit. On the surface Chillproof provides a windproof and water-resistant barrier to the elements. The high loft hollow fleece holds air which your body heats to keep you warm with minimal bulk. Any moisture is quickly wicked away and excess heat or water vapour will pass through the one way semi permeable membrane to prevent over heating. This Chillproof Long Sleeve Chest Zip Top is made of Chillproof material with an inbuilt reflective function. It provides the ultimate versatility by being able to zip up for 100% warmth and protection, or zip down when the sun comes out or your work rate goes up. It also has a high collar to keep your neck warm. Sharkskin Chillproof is ideal apparel for all water sports including diving, snorkelling, jet skiing, all paddle water sports including SUP, surf ski and outrigger, wind surf and kite boarding, sailing and also as a second layer under wetsuits for surfers and ocean swimmers.