I love this undershirt. I bought one (along with the leggins) last winter to wear under my XC ski clothing. Next I took it on a 5wk walk across Spain this spring. Although I didn't need to wear it much on the walk I lent it to several of my friends who were walking with me and who needed a little extra warmth! My sister was one and I promised her one for her birthday! I found it quite roomy and could have probably bought a medium for myself....hence I bought the medium for my sister. It can be squished into a ziplock bag taking no space in your pack. It is warm and washes and dries quickly overnight. All in all a very useful item for travelling!
Jenn, BC