Good tread. I use them outside on my deck steps. It poured for 3 days after purchase and still no slipping. However, the treads and the wood steps underneath are still wet so it takes a long time to dry. I worry about mold in wet, humid climate, but they're washable (soap and water or possibly a pressure washer (I haven't washed them yet). But for the price, I'm very happy. Dogs don't slip on the slick wood steps anymore.