Xl is really only for very wide shoulders. My 17 cm are too narrow and M is here perfectly. But only on my mattress, my very soft Viskoauflage I get neck strain sink through. Here S would be better and even in a waterbed probably the right size. So shoulder height and support is necessary to observe together. Since I sleep in a cold room the pillow is initially very stiff, I advance on where I put heat a hot water bottle along with pillows under the covers. Characterized the pad is softer, it responds to ambient temperature and body heat. Everything fits you sleep very relaxed after a settling-in period.
