The Cover Cap is made from tough, durable woven polyethylene and is designed to protect your spa or spa cover during the harsh winter months. When the spa is closed for the winter, the Cover Cap with a 38” skirt fits over the rigid cover and is long enough to cover the sides of the spa skirt. The Cover Cap is complete with elastic hem to secure it for the winter. When the spa is running all winter then the Cover Cap with a 12” skirt and elastic sewn into the hem, fits easily over the rigid spa cover to protect it from the winter elements.