Covermates Elite Outdoor Chair Covers are made from 300 denier polyester fabric that has been specially treated to repel precipitation and protect your furniture against harmful UV rays. Unlike other covers, our Elite material is light in weight and won't become stiff in colder climates. These covers were designed with a variety of special features like: a built-in mesh vent that allows air flow to promote air circulation needed to prevent mold and mildew buildup; elastic hem band sewn at the bottom of the cover for a secure, snug fit; and a 360° drawcord locking system and two buckle straps in opposing corners providing security and extra durability during extreme weather conditions. All Covermates Elite chair covers come with a 3-Year Manufacturer's Warranty so you can purchase with confidence.