I bought these pads to use while working on vehicles. Basically, if the car lifts off the ground in any way, I don't want it to roll. My use is important as I don't intend to use them to prevent rolling over hills or slopes and I don't expect to put much pressure on them. I've seen reports of people breaking them, but I've crushed fairly strong metal products with a car so abuse will destroy the products, whatever they are. Use it right and these things are great. I would also like to add thatβ¦