Answer: on normal campings you can use a simple ultra lightweight foam mat (the ones you use for doing your garden work on your knees), or a floor mat. In cases you are outside the campings and more adventurous, like in the mountains, in the fjords in Norway, in the forest, etc. we advise to use a protective mat which is more thick, like a carpet tile or even a classic coconut mat (without holes) or a wooden or metal plate under the flat-jack for extra protection against tree roots in the forest, stones, rocks, etc. Always first remove any big stones, etc. before you put up your recreational vehicle and use your experienced camper brains to decide whether the place is suitable for using your flat-jack.