3/2 Marathon Sessions Back Zip Wetsuit For Men We spent years developing our innovative StretchFlight neoprene. And what it generates for the 3/2 Marathon Sessions Back Zip Wetsuit is the superior warmth and comfort you need, plus all the flexibility you could ever want. Bluesign® certified, this eco-friendly wetsuit also has a lightweight feel. So there’s no worry about feeling dragged down. And as for cold temps and water blockage, you’d better believe our R&D team dealt with it and has it dialed in with an infrared thermal lining that will transform your body heat into warm energy. StretchFlight neoprene for increased warmth and comfort without sacrificing flexibility 24% less CO2 emissions per wetsuit Limestone-derivate eco-friendly neoprene made from scrap rubber tires and Bluesign® certified Thermal Smoothie durable textured neoprene, retains heat and blocks wind [chest and back] Lining: WarmFlight® x1 Far-Infrared thermal lining, transforms body heat into infrared energy to generate and maintain warmth External seams: Liquide Flex seal Internal seams: GBS [glued and blindstitched] seams for maximum flexibility and minimal water entry Taped internal seams Entry: Back zip entry Key loop Aqua Alpha, non-toxic, water-based glues Drainage holes 83% Nylon, 17% Elastane