The pillow consists of two layers, so to speak. First, there is the water bladder, and about then is a foam pad. Through the cushion has not directly the cold water on the head. At first everything was great. The pillow so self centered, no matter how you lie.
It is not centered on the pillow, but in one of the outer third, as "slips" the bubble under the head off, and you just lying on the cushion.
Eventually, the foam layer is then also even wrinkled. A normal pillow would shake now .... but with a filled with 3l water bladder? After then this bubble has expanded to 3 months something that water is displaced from the head to both sides and one lies back flat on the foam. Dia is aware that you can top up a glass of water and attempt to restore the original deck feeling again. Because of other negative points, the cushion is however firstonce disappeared in the closet, and I sleep on a standard pillow.
Conclusion:
The principle may well be orthopedically sensible. I was however, not convinced of the reasons given above.
