For serious winter riding in all conditions, the Alpha Ultimate Insulated Jacket brings premium insulation to this do-everything-well jacket.Castelli´s Alpha RoS 2 Jacket set a new standard in winter cycling comfort.The Alpha Ultimate Insulated takes that up a notch with stretchier fabrics and Alpha insulation that provides warmth without bulk.The jacket is lighter and more comfortable, with similar warmth and breathability.In fact, it´s almost 30% lighter, with more stretch to feel even more comfortable.The fabrics make it possible.The fully waterproof and highly breathable Polartec® NeoShell® outer fabric has a high level of four-way stretch.This layer keeps wind and rain out while also letting sweat escape.The insulation is Polartec® Alpha® active insulation, which provides incredible warmth for its weight while also aiding in breathability.Fabrics alone don´t make the jacket.The front has one zipper for the insulating layer and a separate zipper for the outer shell, so you can open the outside for ventilation while keeping the insulating layer closed.This allows for better overall ventilation during a climb or effort, yet you´ll be drier when you close everything back up for the downhill.All the other features are carefully considered to make this your ultimate winter jacket.Espeficitations:Waterproof Polartec® NeoShell® 4-way stretch outer fabric.Insulating layer in Polartec® Alpha® active insulation for more warmth and breathability.Critical external seam taping for effectively waterproof protection in normal riding conditions.Double-layer Alpha construction separates insulating layer from wind/water barrier to let you better regulate ventilation.Double-opening YKK® Vislon® zipper slides easily for better regulation of airflow.No-sew bonded hem lies flat and seals out wind.Anatomically shaped cuff integrates with glove to prevent cold wind or water from entering at wrist.3 rear pockets.Reflex zones at lower back, on shoulders, and around wrists.Zippered secure side pocket for valuables.