After a lot of on line research on merino tee shirts, I selected the Ibex U-Sixty. I am very satisfied with the selection. I had some reservations about the seam in the back but it has not been a problem. The relaxed fit is good not too tight but not baggy.This is a lightweight shirt that keeps you dry and warm. I haven't tried it in the summer, but I have a friend that wears one in warm weather as well. I find this to be less itchy than the icebreaker base layers I own.
This is a superb product. Perhaps the most comfortable of all the Ibex products I own. The Zephyr, is a favorite, since I am a skier. However, this shirt is truly amazing. It wears exceptionally well. I can sleep in this and wear it the next day. It looks great with canvas shorts or just about anything. I have two of these in short sleeve, and one in long sleeve, and they are wonderful shirts, with few equals.