The Aven 17010 Adjustable Circuit Board Holder available on Amazon has a design flaw that keeps a good product from being great. The spring used to compress the PC board digs into the plastic upright causing it to chip away at the plastic and, if you spin your PCB the wrong way, causes the PCB to rotate in the opposite direction you were trying to spin it. This is very frustrating because soldering is already a 3 handed job.
The bushing is installed between the spring and the plastic upright. You will need to remove and reinstall the "C" clip to install the bushing. The bushing significantly compresses the spring, limiting the amount that it can be compressed after the bushing is installed but there is still enough room to compress the spring to remove/insert the PCB without having to adjust the position of the upright.
Inserting the metal shaft into the bushing is a tight fit but I did not want a sloppy fit that could cause the PCB to wobble while you are trying to solder a joint.
Support used so that the spring will fit on a flat surface when inserted into the bushing.