Nanoflex really is at the cutting edge of fabric technology. We go into the science in more detail below, but the result is that Nanoflex actively repels water. Where other garments let you down, the Nanoflex 2 is the answer when you're wondering what to wear in the rain Just like Castelli's Thermoflex fabric, Nanoflex is warm and breathable. It's extremely soft to the touch and traps a layer of warm air next to your skin. Its secret, however, is that it's coated with millions of microscopic nanofilaments. This nanotechnology treatment causes water to bead and run off. The Nanoflex 2 bib knickers aren't 100% waterproof, nor does Castelli claim that they are. They will, however, keep you drier than virtually any other bibs out there The Nanoflex 2 knicker features the Kiss Air seatpad, incorporating many of the features of Castelli's top-of-the-range chamois. In any cycling garment, comfort is paramount and the anatomical shape of the Kiss Air pad ensures maximum comfort, no matter how long you're on the bike. Dual density foam is used to provide variable thickness - padding where it's needed and less where it isn't, to maximise your freedom of movement on and off the bike. Finally, a brushed microfibre top layer, with superior softness and an anti-bacterial treatment eliminates chaffing and saddle sores As a cyclist, your power comes from your legs and much of this comes from your knees. That's why it's important to keep them warm! The Nanoflex 2 knicker gives 3/4 length coverage, with silicone bands at the knees to keep them in place. When getting those extra training miles in means venturing out in the dark, reflective Castelli logos will help keep you safe by making you more visible to other road users Whether it's cold, raining or both, the revolutionary Nanoflex 2 knicker will have you prepared for anything Features: Nanoflex fabric provides outstanding warmth and stretch, with water resistance Minimal seams for maximum water resistanceKISS Air seat pad for all-day comfortMesh bib straps for breathability Reflective screen-printed Castelli graphics on both legs allow you to be more visible to other road users Silicone gripper ensures the knee stays in place Temperature range: 10-20°C Fabric: 86% Polyamide (Nylon), 14% Elastane (Spandex) Weight: 215g (size S)With roots dating back to 1876, Castelli has been at the forefront of fabric technology for almost 40 years. Alfredo Binda, Gino Bartali, Fausto Coppi, Jacques Anquetil and Louison Bobet were but a few of the legendary athletes clothed by Castelli. More recently, Bernard Hinault wore the first windproof jersey when he won Fleche Wallone. Castelli made that too! Buy Castelli Clothing from Chain Reaction Cycles, the World's Largest Online Bike Store.