Over the years Kent has used a number of different things to place on top his jack stands to prevent damage and for added security. He has even tried some of the commercially available jack stand plastic covers. Nothing has proven to work better than the special cut reinforced hose shown here. This is just not regular radiator hose. The weight of the car will usually cut through that. These two covers are cut and sliced from very expensive heavy reinforced rubber hose.
Take a look at the picture below and the video above to see how Kent uses these protectors.