Made of natural coir, a dense fiber that is naturally molded and mildew resistant. Coir is a renewable resource that is durable and coarse, excellent for scraping shoes clean. Vinyl-backed for increased durability and to help prevent movement, coir doormats are weather tolerant absorb moisture, and retain their shape. For best results keep in a sheltered area such as a covered porch, keeping extreme moisture and sunlight to a minimum.