Jonny Heinkenwrote a review of Castelli Alpha Wind Jersey - Long-Sleeve - Men's on September 14, 2016
The Alpha "jersey" is really a light, aero-fit jacket for fast riding and climbing in cool/cold and/or windy/misty/drizzly weather. Castelli officially rates it for use from 45 to 60° F.
Pair the Alpha with a light-weight l-s baselayer in cool weather (like the white Castelli Flanders), and with a heavier baselayer in colder weather (e.g., Flanders Warm or Wool).
Pros: (1) The thermo-regulating built-in interior "vest." Yes, great for climbing. Hard to describe. You have to experience it. (2) Love the elegant, understated look, and the new collar treatment. (3) The raw cut sleeves fit perfectly inside Castelli's 'lightness' or 'nano' gloves.
Note: The Gore WindStopper textile used in the Alpha is water-resistant, but not water-proof (as Castelli admits on their website). This jersey does a great job in misty or drizzly weather. However, as I discovered in a recent 2-hour ride under steady showers, the jacket will eventually soak through. So, if the forecast is looking really wet, you WILL want to bring along a lightweight, taped, water-proof jacket such as Castelli's "Riparo" or "Tempesta" jacket.
Sizing: Size up +1. Part of Castelli's Rosso Corsa (race) line. Designed for, and tailored for, the fit/athletic rider. Wear snug and aerodynamic.