The rack is light, compared to a rack build from wood. Still I am able to mount quite heavy equipment (2U preamp, 1U speaker managment system, 3U power amp, totally about 20 kg) without problems. But since the rack mounts are quite thin compared to a normal flightcase I handle it with care. These lightweight racks are best suited for mounting light equipment.
If you put something heavy on top of the rack, it will bend down. If you want to use it together with other, different racks, it has to sit on top of the stack.
Still the rack offers good protection for your equipment and it does not cost as much as conventional racks.