Clearly marked on all sides "DO NOT DOUBLE STACK" There was a large hole where the forklift ran into the back, which was careless but only cosmetic. But just to make sure the destruction was complete - they double stacked and completely destroyed a $4000 packaging machine. It was the last one available in the US and we had it shipped from NJ for a large time sensitive project. Now we will be waiting for 4-6 weeks for a replacement unit to ship from Italy. Pick a quality shipping company and stay away from YRC.