I've used them a lot when changing the oil. I didn't feel their work as they were always easy to remove after the job was done. But recently I completely forgot about them, having done the work, I started the car, released the handbrake, turned on reverse, my car could not move, of course I slightly pressed the gas pedal, it still remained motionless , kinda weird I thought, so I hit the gas harder and my car pulled out of my garage, around that time, I finally remembered, the big reds were working. Yes they worked but after flipping they flattened and failed. I will buy another pair knowing they do their job.