The Mallard Waders are constructed of 100% waterproof 3.5mm neoprene, which stretches for a personalized fit and has a multi-directional puncture resistant covering for durability. This expandable version has an extra 16" in torso length and extra roomy thighs. They provide the ultimate waterproof and insulating protection for cold wading applications. With 1000 G. Thinsulate Ultra Insulation in the boots, these waders keep feet warm, dry and comfortable.