I've used these for my QSC KW153 PA speakers, which are quite tall and heavy at 110 cm and 40 kg. Even when I raised the speakers several notches up from the lowest level, the stands are very stable. The locking mechanism means there's no wobbling or unintentional rotation of the speaker. I really like this feature, as the usual wobbling is completely gone, and I don't have to worry if the speakers no longer are aimed correctly during a show.