What is the Best backcountry skiing Base layer top?

Our favorite all around backcountry skiing base layer top (or downhill skiing) is the Rab MeCo 165 Long Sleeve Zip Tee (I believe the new version is now called Rab Merino+ 160 LS Zip Top).  The Rab MeCo shirt does a fantastic job of keeping you warm while wicking away sweat, keeps from getting smelly/stinky, and dries quickly. It's also super comfortable, and we end up wearing one all winter long for skiing, camping, climbing, snowshoeing and hiking. The half zip is also nice for regulating heat. The thickness of the Rab MeCo 165 long sleeve shirt makes it ideal to wear when temperatures are between 32 F and 0 F.  There's also a Rab MeCo 165 hoodie version in both men's and women's, which you might like for staying extra warm or while winter camping or ice climbing.

When temperatures are near or above freezing, you might be more comfortable and sweat a little less when active wearing the Rab MeCo 120 Long Sleeve or Short Sleeve top.