Nothing ruins a ride faster than catching a chill. Except maybe a flat tire. Or slushy conditions. Well OK, there are lots of things that rival catching a chill, but we still don't like it. So as the seasons change, we start thinking along the lines of layers, and this inevitably leads us to the Castelli Flanders Warm Base Layer. The Flanders is made with a durable SottoZero Fleece that insulates and wicks. Dryer, after all, is warmer. Mesh inserts provide ventilation in the underarms, just in case you overheat, and the flatlock stitching and flat hems mean the Flanders will fit comfortably as a piece of layering gear. Castelli recommends it for use in 23 to 46 degrees Fahrenheit, and, while this range may seem excessive, we find that the Flanders gets the job done in all conditions when layered with the right outer layer. The Castelli Flanders Warm Base Layer - Men's is available in six sizes ranging from X-Small to XX-Large in the color Grey.