The Waterhog Classic is covered in square, crush proof, reinforced nubs, which are designed to scrape off unwanted dirt and trap it inside themat. These nubs also allow for water to sink beneath them, not soak into them, making a weatherproof mat and providing a clean interior. The Waterhog Classic mats also have raised rubber around the borders, otherwise known as the “water dam”. This border helps keep water and dirt inside the mat, keeping it off the carpet and floors. These Waterhog mats also come in 18 different colors, as well as 18 different sizes. You’ll have no problem finding the perfect Waterhog mat for your needs!