Steve 2 One of the black risers has some really heavy casting left in one of the teeth/notches that prevents it from being used. I have limited tools so I'm currently stuck with a non-functional pair of jack stands. I got lucky with the first two I used and just needed the other two the other day and found this situation. Just disappointing/bad luck. Quick quality check would have caught this issue. Otherwise they are as advertised and would have been an easy 5 stars.