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Double-layer structure offers plenty of protection
Castelli presents the Alpha 150 winter jacket, which was developed to mark the company's 150th anniversary in 2026. The jacket is the result of twelve years of continuous development of the original Alpha series, which was launched in 2014. The concept aimed to create a winter jacket made from the most innovative materials available, offering warmth and comfort in a wide range of temperatures. The Alpha 150 is suitable for cold, dry days and offers protection in wet conditions, but not in prolonged heavy rain.
The new jacket utilises Castelli's exclusive use of Polartec AirCore technology, combined with a separate Polartec Alpha insulation layer. This combination of materials enables optimum performance in temperatures from minus two to ten degrees Celsius. The AirCore material acts as an outer layer and provides high breathability combined with low weight, windproofness and water repellence. The Alpha layer on the inside regulates heat and moisture thanks to its loosened fibres, mesh core and hydrophobic properties.
AirCore technology: Technical features
Polartec AirCore was first introduced in Castelli's Perfetto RoS 3 jacket and is completely free from PFAS-based chemicals. The material is made from recycled polyester yarns that form an extremely dense membrane. This membrane keeps out the elements while allowing air permeability. During development, Castelli and Polartec prioritised breathability over water repellency, as moisture from sweat on the inside is just as big a problem as rain, slush or snow on the outside.
The AirCore material achieves an air permeability of 0.7 cubic feet per minute (CFM), which makes it practically windproof. The hydrostatic pressure test resulted in a value of 5,000mm water column. This means that normal rain would have to fall with 6.25 times the force to penetrate the material. The combination of windproofness and water resistance with simultaneous breathability is created by the precise construction of the membrane structure, which allows only minimal, imperceptible amounts of air to pass through.
Alpha insulation technology
The inner Polartec Alpha insulation layer was originally developed for the US Special Forces. The material is characterised by high breathability and quick drying, but at the same time adapts to changing conditions by effectively regulating heat and moisture. The loosened fibres with a mesh core and hydrophobic properties retain heat when it is needed and release it when it is not. This adaptive function is created by the free-floating structure of the fibres, which react according to body temperature and activity level.
The combination of both Polartec technologies in the Alpha 150 provides protection from the elements with high stretchability. The close fit makes the jacket feel like a jersey, not a heavy winter jacket. Steve Smith, Castelli Global Brand Manager, explains: "The Alpha has been one of our most important winter products for years. Amateurs and professionals alike call it their favourite jacket in cold conditions. With the Alpha 150, we're raising the bar even higher and delivering the best winter jacket we've ever made."
Practical features of the jacket
The Alpha 150 has a double front opening that allows independent ventilation of the AirCore and Alpha layers. YKK Vislon zips with top and bottom openings ensure easy gliding. The high collar, double cuffs and covered zips provide additional wind and rain protection. A zip pocket on the front holds keys or money, while three back pockets provide space for food and tools. Reflective piping on the pocket bottoms increases visibility in low light conditions.
The double front opening allows the outer layer to be opened during intense exertion to accelerate moisture wicking over a larger area, while the inner layer remains closed and keeps the torso warm. By separating the two layers, Alpha acts as a free-floating layer that wicks away moisture better and dries faster. At the same time, it is softer and more comfortable than traditionally bonded, three-layer materials. The high collar helps to retain heat, while the double cuffs seal the glove and prevent cold air and water from penetrating.
Technical data
Material structure
- Outer layer: Polartec AirCore (PFAS-free, recycled polyester yarns)
- Inner layer: Polartec Alpha insulation
- Water column: 5,000mm hydrostatic pressure
- Air permeability: 0.7 CFM
Equipment features
- Double front opening for independent layer ventilation
- YKK Vislon zips with bidirectional opening
- High collar with double cuffs
- One front pocket with zip
- Three back pockets
- Reflective piping
Available variants
- Price: 339,95 Euro >> available here
- Gentlemen: Light Black/Black, Mango Mojito/Black, Brilliant Orange/Dark Grey, Deep Bordeaux/Clay
- Ladies: Light Black/Black, Deep Bordeaux/Brilliant Pink, Hibiscus/Black
- Temperature range: -2°C to +10°C
