Great to lay on while meditating.
When I first started using this, it was very tender on the back of my neck. The two knobs are perfectly situated to find the exact areas of muscle tension.  You can move it around to find more sensitive areas.  After using it for several weeks, I no longer experience that tenderness, and my neck feels less tight.  I now lay on this while meditating. This has helped me significantly, but it did require persistence.
Rating: 5 stars