Weatherproof, Outdoor Lounge cushion covers (as used on both fully upholstered Outdoor Lounge collections, integral cushions on seating items and some optional cushion pads) use Sunbrella® Rain 100% solution dyed acrylic fabrics (USA) or Sunbrella® PVC/Textile fabrics (USA & Rest of World). Sunbrella® PVC/Textile fabrics are similar to a traditional PVC sling, but with the addition of textile yarns within the weave to offer increased comfort and the addition of a lamination layer on the reverse of the fabric to aid water resistance. Outdoor Lounge cushions are designed to be highly water resistant, so no water can enter into the cushion filling itself. In the unlikely case that any water does penetrate the outer cover, the construction of the cushions themselves - including a water resistant but breathable inner liner and reticulated foam & dacron core - allows water to freely pass through the interior and exit underneath. Open mesh bases on the outer covers assist by aiding airflow within the cushion, further speeding up the drying process. The covers on most base and back cushions are removable and the interior of the cushions is water repellent. However, due to the highly tailored construction of these cushions, Gloster does not recommend removing the covers unless it is for replacement purposes. As with any item left permanently outside and exposed to the elements, regular cleaning is recommended. We also advise furniture is covered in the winter months if possible.