This depends on the anchors used, the wall, the type and size of set screws used, and the load point.
Our structural engineers have calculated that if you use large lag bolts (6x 5/8 or bigger) in a real concrete wall using Hilti 2-component epoxy, the steel bracket can hold up to 2500lbs with a security factor of 4 (in theory, 10,000 Lbs.)
In this case you may use lag bolts or plain threaded rods with washers and nuts. Please remember that the higher the bolts are situated the better, but also note that going too high or low will cause them to interfere with the bracket connecting properly - See the diagram below for reference:
As you can see above, regarding the female bracket, if you position the lag bolts too high, the male cannot slide in anymore. Position them too low, and the female cannot close at the bottom.
Ultimately, each individual install will determine the maximum load capacity of the shelf.
An example of an extremely weak install would be one in which you only use 2 drywall anchors. The shelf will not hold more than 5lbs distributed over the length of the shelf at 8 inches of the wall. And if you wiggle it up and down, it will come undone within seconds. So remember these two key points:
1. The shelf is only as good as the male bracket's connection to the wall is.
2. The connection to the wall will always fail before the bracket does.
Check out this quick video primer on the steel bracket to learn more:
To learn more about Hovr's steel bracket, head over to our Steel Bracket FAQ page.