The Gerona thermal TPU tights are designed with TPU treated outer Lycra so you can stay dry and a soft microfleece lining that traps warmth and wicks away moisture from your skin to ensure you can continue to ride over the winter season. Key FeaturesTPU coated microfleece Lycra,Self locking front zipper,Reflective bands on the bottom/back of the legs,Self locking reflective ankle zipper,Double Lycra ankle gripper,B14 pad.TPU fabric is created by laminating the membrane to high-performance textiles that are extremely breathable, then sealing them with an innovative solution for 100% waterproof protection. The TPU membrane contains microscopic pores, which are a 1000 times smaller than a drop of water, but 100 times bigger than a molecule of moisture vapour. So whilst water droplets cannot penetrate the TPU membrane, moisture vapour can easily escape.