I use the green indoor outdoor carpet you can pick up a home improvement store. Cheaper than an RV mat. Looks like grass. Seems to keep dirt and sand out of unit better. Seems to hold up better in the sun. Been thru 2 RV mats and still have the large piece of grass we started with even though it's cheap enough that I'll have no problem throwing it out when needed. Lay it grass down in the driveway and hit it with a hose and it's clean.