Got some of these to mount some of Thomanns LED lights on some scaffolding that was being used as a stage. They are really sturdy, and easy to use, and fitted on the various diameters of the different parts of the scaffolding. Couldn't find anything similar for anywhere near this price.
Only slight issue is that is the placement of the bolt in relation to the part the light is mounted on. If you are using these on a larger diameter pipe, the bolt can get in the wal of the light fixture, limiting your options for angling the light.
However, for the price, they are great.