Love these spotter arms. They fit my Iron Bull Strength rack very snugly (the hole size is slightly different, but the tubing size matches well) and feel extremely solid for barbell movements. I also use them along with a pad as a makeshift leg roller to hold my knees in place, and as a DIY preacher curl attachment. The latter works surprisingly well in my setup because the spotter arm can rotate, but is mostly stable due to the snug fit on my rack. As others have mentioned it is unfortunate that there is no hole for a magpin to fix it in place, but I haven't found this to be a huge issue for my purposes.
Performance
Value
Build Quality