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This article originally appeared on BikeRadar
The back has a mesh panel and ventilation flap and most of the sleeves have a warm waffle pattern fabric, as does the zip-up waistcoat that insulates the chest. It’s fixed at both sides, but if you overheat, the Alpha allows you to open the main zip to expel moisture without chilling your core.
All the insulation moves independently of the shell, giving great freedom, and Castelli's raw edge cuffs and waistband seal perfectly, lying totally flat for excellent glove-like fit and no draughts. Even the articulated collar is super snug. Practicalities are taken care of by three drop pockets and two zipped, one rear and one on the waist.
