BikeParka Waterproof Ripstop Bicycle Cover Style Urban - Color Emerald Polyester Ripstop fabric as standard. It outperforms nylon as it won't stretch if pooled with water. It's also really tough Polyurethane (PU) coating gives full weatherproofing against rain and wind. Fully seam-taped to protect the stitching and keep any water from seeping through. Elasticated wheel fit UPF50+ gives the best possible UV fabric protection, to help stop fabric breaking down in the sun and keep its color. Velcro lock-through panel AND handy Stuff Sac that attaches to your bike.