Dropped one star because the first set I ordered were defective in that they literally crumbled under pressure. I use them to jump a curb for my RV and while that RV weighs 53,000 lbs the maximum weight these ramps should have experienced was 15,000 lbs each for the rear axles but yet they crumbled with big chunks breaking off after 3-4 uses. I contacted the seller and they immediately shipped me new ones and they have fared much, much better with the rubber clearly being more flexible so I suspect something went wrong with the vulcanization process with the first set because I have never seen rubber chunk like that (like a crumbly cheese) . The new set deserves 5 stars but because of possible quality control issues I gave them 4 stars overall.