BEHIND THE PRODUCT Temperature regulation is the key performance indicator of any base layer, and this is especially true for a winter version. But winter poses a specific host of challenges not found in other climaCodes, namely in the form of added cold air and your additional layers. This is where our new Winter LS Skin Layer fills the gap, tuned with a thicker knit “weight,” taller collar, and more stretch than our Spring/Fall version for boosted insulation and flexibility under your outer apparel.