Armed with NEMO's top-performing OSMO fabric on the fly, Mayfly OSMO is a notably durable backpacking shelter for adventurers ready to hit the trail. A proprietary composite fabric, OSMO is made from 100% recycled polyester and nylon yarns and scores 4x better in water repellency than standard tent fabrics - all while stretching 3x less when wet. OSMO fabrics meet fire retardancy standards without the use of added chemicals and are treated with PFAS-free waterproofing.