These came with my Behringer DR112DSP speakers which are quoted as weighing 17kg and the stands are rated at 20kg max. I would not use these two items together for a show as the weight of the Behringers is a challenge for these stands. They flex quite disturbingly with the 17kg on them. They have not gone to waste though, they now serve as lighting stands, as use for which they are much more suited. I would not recommend using them for speakers weighing more than 10- 12kg.
Pros: lightweight, good damping and really excellent easy to use knobs and locking pins. Good value for what they are capable of.
Cons: I would not recommend using them for any load much more than half of the rated maximum.