Size M. I am 170 cm tall, with a small belly. Probably S would also fit. I consciously chose M as a stationary insulation where it will be put on other clothing. Fits perfectly. One month of use but the temperatures were just right for that. The lowest recorded temperature was minus 23°C. In temperatures below minus 15°C, I wore it over a thermal shirt, 200 weight fleece and a padded jacket or down sweater. This was with low activity. The padded jacket was necessary because I felt cold. I also wore it under the Pilgrim and marched with a backpack. In temperatures up to -15°C, "on its own". The long side pocket zippers allow access with the hip belt fastened to warm your hands. The vents improve the microclimate when you're trekking through snow with a backpack. I give one star less because the hood isn't perfected. Overall, I recommend it.
