PostureTech 660 Response Contains a 4cm Geltex filling - a gel infused foam that is the most advanced sleeping material available. The perfect environment for cool, dry sleep. Sealy Smart Fibres provide a Cool, Fresh, Dry and Hypoallergenic sleeping environment. Endorsed by Allergy UK for the reduction of house dust mites. Eco-friendly Tencel fibres help keep you cool and dry. Correctly supports and aligns the spine in its natural shape, helping to reduce aches and pains.