When it comes to cold-weather cycling, every member of the Competitive team has their own approach to layering; however, we virtually all share a common starting point: a long-sleeve wool base layer. Giordana's Wool Blend Long Sleeve Base Layer for Women serves as the ideal base of winter cycling operations because it combines the supernatural powers of cycling's original wonder material, merino wool, with a little help from the synthetic catalogue in order to maintain a contemporary fit. Giordana's calling the resulting material blend Mimosa. We don't quite understand the name choice, but we don't care what it's called as long as it starts with wool. Merino is a cycling staple that may no longer define the top racing jerseys and shorts as it did when all bikes were steel and cassettes were nowhere near the double digits, but there's a good damned reason why we continue to turn to it when the weather turns toward winter. It's breathable, it's the original hollow-core fabric, it stays warm if it gets wet, and it's naturally odor resistant. Every material used in cycling kit breathes and chances are good that you'll be wearing an anti-weather top in inclement conditions, so the real standout qualities for wool are the way it insulates and the odor resistance. There are a glut of synthetics in the base layer industry described as hollow core yarns, and wool is the reason why. They're all trying to mimic wool's ability to trap countless tiny pockets of air in order to create a microclimate of warmth, and--though they've basically succeeded in copying it--wool is still the original. It also stays warm if it gets damp, so you won't pay as steep a price if you over-layer and overheat during winter climbs. This timeless material is supplemented with nylon, which holds its shape and offers more support than wool, and spandex, which helps the four-panel construction disappear under mid and outer layers by stretching as appropriate.