Castelli Alpha RoS 2 Chaqueta Mujer, amarillo

This jacket is exactly what Castelli thinks the perfect winter jacket should be. Castelli started with a list of things they didn't like about the current jackets and set out to solve them—and in the process make their best jacket ever.

The first issue to resolve related to moisture management. Even the best of the currently available fabrics provide a good level of breathability but can't keep up with the sweat generated during high-intensity riding. So Castelli invented a double-layer construction that allows you to open an outer wind-protection layer while keeping the insulation layer closed and thereby allowing airflow inside the jacket to evacuate moisture while avoiding direct contact with the skin. On a long climb you can completely open the outer layer to allow moisture to escape, and when you start the descent you can close the outer layer and are completely dry inside. It works so well that sometimes it feels like magic. New for this year is a softer, warmer 3D insulation-layer fabric that provides better warmth, moisture management and fit.

Next Castelli focused on the openings: neck, waist and, most of all, wrists. The neck comes up high and is shaped to move with you, whether you're standing or in an aero position being a January hero and attacking your mates. For the waist Castelli created a stretch layer with a silicone bead that lies flat and completely seals out wind without bunching or riding up. New for this year is a brand-new double-layer wrist opening with an inner layer to go under your glove that seals tight to your wrist, and an outer layer that goes over your glove so that any rain will roll down the outside of the glove and not end up inside.

Of course, the ultimate jacket will also hold up well in wet conditions, so Castelli used GORE-TEX INFINIUM WINDSTOPPER fabric along with waterproof seam taping on critical seams around the shoulder. Other seams are hidden out of direct water flow, and the water-repellent treatment on the fabric is sufficient to prevent most moisture from entering. Castelli calls it "essentially waterproof," using their own subjective judgment to find a balance between water protection, breathability and comfort. It doesn't mean that no drop will ever come in, but Castelli test teams do longish rides in real rain and stay completely dry.

All these features make it a favorite of the Team Ineos riders, and the most versatile performance jacket for cold-weather training Castelli ever created.