RockyMRanger 3 Seater Waterproof Swing Cover Garden Patio Hammock Hanging Chair Canopy YS21N This item is made of 210D woven polyester(Oxford) material with PU coating, which is water-proof. And this cover has another important feature for water proof: Along the seam, from the inside, there is the seal tap. The tap provide much better function for water proof.