This is a spacer. I've run them in the past with no issues so I'm running them again. I tightened them all to 100 ftlb as my rigs required. There is no red locker for me, I rent things for repair and that bothers me. Not once did one come loose and twist her hard. I will update if I encounter any problems. While at a speed of 75 km / h there is no vibration.