Does anyone remember a bed that prevented bedsores?

Hello,
Years ago I read of a very expensive and special bed that was for preventing bedsores. It contained tiny glass beads inside, I guess, a bag-type of container, that shifted as one's weight was shifted. I cannot remember the name of this bed and I have not been successful in locating anything with google. I was initially thinking that it was the Duxiana bed, but it isnt. Cant remember the name. Anyone here remember anything of this sort?
Thanks.
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