Behind the Technology of Lavacore Lavacore is a technically advanced fabric, constructed and engineered exclusively for water sports requiring the ultimate in thermal control and superior comfort. This unique synthetic construction closely matches the stretch and movement of a traditional lycra rash vest, whilst providing the insulation qualities similar to that of a Neoprene wetsuit. Close to the skin, Lavacore"s soft internal fleece and high 4-way stretch produces the ultimate comfort>warmth>weight ratio, a true leader amongst any fabrics within the water sports industry. Wet or dry, hot or cold, Lavacore helps control your core temperature longer, whether worn as a stand alone garment, or under your wetsuit or clothing. OUTER lycra layer is a 180 g/sqm knitted knylon wrap knit Tricot with water repellant treatment to ensure fast water run off and anti wind chill properties. INTER layer is an impermeable breathable Microporous high stretch PU film which is wind proof and breathable allowing perspiration to be drawn away in hot conditions. INNER Fleece layer is a 240g/sqm 4 way stretch polyester fleece with elastane. It has Anti Pill treatment, as well as Anti Microbial treatment to reduce odor and eliminate bacteria.