anti bedsore mat (Coventry CV1)

This is a mat which goes under the sheet to help prevent bedsores. They used to be given out by the district nurses to people who spend a lot of time in bed. It is a medical aid, but they never collect them.
This one has not been used for several years and has been recently laundered to freshen, with non allergenic suds.
please give your reason for needing this item.