I use them. They say they are 7kg but add hose, gneck, brush.
fully extended they are a bit whippy, but can't fault strength and overall rigidity. They send you a 's' shaped gneck with an 18" vikan, I would try to get them to change the brush as that one is far too heavy, I got 12" vikan mono and they work well together. I've still got one from 5 years ago thats working fine. ( the previous version, heavier)