I have been running in long sleeve tees for many years. At first it was to keep the sun off on long trail runs in the deserts of Arizona. "How can you run in a long sleeve shirt" everyone would ask. "Everything else is dirty" I would respond. Keeping the secret as to why to myself. Now I run in the mountains of Utah. All of my running long sleeve tees perform about the same. That is, until the Xterra Switchback Long Sleeve Tee. I purchased to it support for the Xterra brand, I thought is was nice looking shirt., and it was on sale. When it arrived I was concerned at the weight of the cloth. Reminded me of a light weight thermal tee. No worries though, I prefer to be warm even hot over cold. My inaugural run was a delight. Not cold, not hot, just right. With this I decided to give it a try at a high altitude trail race in Utah. With snow still on the race course and a heart pounding boulder climb to 10,000 feet for the first of several summits, my fear of a rapid core temperature drop was first on my mind. You know that bone chilling wind that greats you at the top and a wet shirt. Not a marriage made in heaven. As I stepped into the wind I cringed in anticipation of the cold. Ten steps later I realized the shirt was nearly dry and the warmth to my core was secure. At my age I do not run to win or even a new PR. I race for the fun. This shirt added a new level of enjoyment. Now make this shirt with more color choices and I will fill my closet. How about bright green and orange to help out the rescue response teams.