I added these monitor shelves to spread my audio a little out from my work station. The mounts are well built and solid. The only negative thing I can say is the threads are a little tight and you need to be careful not to strip the threads. The front knob to raise up the shelf is also a little tight but it does work.
The installation went great and I would suggest using washers with the screws and anchors. Second, leveling is important when marking the holes to drill in the anchors (Not Provided). However, once properly secured to the wall they seem really sturdy and secure. I have M-Audio AV40 on them for now with a couple PC Speakers on top and I plan to go one step larger in the future. These are definitely worth the price for speaker mounts. They can hold a speakers WxD 25x25 from what I can see.