Neoprene from limestone, which gives it the ecological credential compared to oil-derived wetsuits. More elastic and more durable. All our wetsuits are sealed inside and have a thermal fabric inside to protect us from the cold and facilitate drying. In wrists and ankles they wear a band of liquid neoprene to fix the suit to the body and prevent them from moving. GBS seams, YKK zippers, abrasion resistant knee pads that make them more durable, grooves behind the knee for maximum flexibility, and a long etc. of features that make PREMIUM wetsuits one of the best surf suits. PREMIUM wetsuits are made with high quality materials. We know your demands, world class products for maximum performance. In PREMIUM wetsuits, performance stands out; maximum flexibility and durability, sealed seams and an adjustment that feels as if it were custom mad. Read less