First, I was expecting this to be in par to wood racks that I have; this beast is a different ballpark. All of the tubes are thick, heavy steel. This is a very heavy unit. You'll want to mount the vertical strips first and then add the arms otherwise this will be too heavy for one person. Provided are expansion bolts. If you want to mount to wood, you may want to pick up lag screws. I used last screws to mount directly to a wood shelf. Each vertical bracket has 3 holes for mounting. Mount one screw, level, then add the other 2 screws. Repeat in the other side. The arms bolt in with two bolts with washers each. There are multiple mounting options allowing 2-3 holes between arms. If you have something overly large, you may even choose not to mount all the arms. The bolts tighten with the provided Allen key. Each arm is foam wrapped, and they all also have a neoprene sleeve over the foam. The arms are very well protected. The arms are also slightly angled upwards to ensure nothing rolls off. This will easily hold a kayak or three of mounted correctly. Overall I am happy with this. It is much heavier duty, heavier, and larger than expected. That isn't a bad thing, however. I'll feel confident putting quite a bit of weight on this.
M Anderson 
