I recently watched a video on Youtube showing how easily the ratchet type jack stands can suddenly fall, with potentially deadly results. I realize they shouldn't fall as long as there is weight on them, but as the video shows if the release lever gets bumped accidentally, failure is possible. Since I use mine frequently, and usually with no one else at home to call 911 in case of an accident, I modified all of mine by drilling some holes & inserting a 1/2 inch bolt thru them. I located the holes so the weight of the car is still on the ratchet, while the bolt serves as a safety. Each one took about 10 minutes on the drill press. It was a cheap & easy way to gain a little peace of mind. I know most of us Volvo guys probably crawl under their cars fairly often, so I thought this posting might possibly keep someone from getting hurt.