Stronger than I expected.
With 35 killo load limit. I got a 50cm and a 25cm to make a 75cm rise. Loaded with my heaviest top, ?? Killo, a big JBL, and there is no signs of wobble or slack. These ext tubes seem to lock together, presision engineered for this sort of work maybe, but looking good too, and I can leave my old speaker stands @ home.
I am solo guitar & looper, strictly minimum sound gear for quick setup & tare down. Indoor venues need minimum floor use, these riser tubes are great for this. Screwed into my sub, and Thomann sensible prices, its all good.