Men's Rho LTW Zip Neck
One of the important factors that I appreciate about Arc'Teryx is the snug fit and excellent arm length. I am 6'5, 215 pounds with a 37" sleeve length and able to wear Arc'Teryx baselayer garments in a large size. For outerwear, I jump to an XL.

makes other merino baselayers look weak
Long-time wool user here, have Patagonia merino 1 and 3 and several Icebreaker long sleeve mid- and baselayers, and Arcteryx LTW has them beat on fit and durability. Patagonia merino is gentle and relaxing but wears pretty quickly and the fit is overall looser since there's no stretch. LTW has a somewhat more "technical" close fit with moderately long sleeve lengths - close to ideal.

Awesome baselayer!
I bought this pullover as a gift for my dad and he absolutely loves it. It has the same high quality we've come to expect from Arc'Teryx, and is extremely comfortable and looks great on him! It's warm but very breathable -- he wears it as a light layer several times a week and it still looks new -- it's even dressy casual enough to wear out. It's fitted, but he's a big guy (6'3", 215) and it's plenty long enough -- size Large is perfect. Another Arc'Teryx staple!

Very well made!!!
Being that is summer time, I've only had the opportunity to wear it a couple times. Came in handy on a brisk early morning bike ride, very comfortable and warm, I normally wear a large, I went with the x-large as it is a slim fit style base layer.