These 1-1/4" thick coiled steel mud mats are designed to scrape mud or packed snow off of any dirty footwear. If the mat gets clogged, all you have to do is to pick it up, give it a good shake and then plop it back down. It's like having a virtual "mud room" and they are effective both inside and outside. Step on them first, get rid of the really messy stuff. A set of Non-Slip Rubber Feet come with each Steel-Coil Mud Mat.