Over excursion from too much power with a signal below the cabinets tuning frequency or inertia damage from a sudden stop after a fall. I'd avoid purchasing a speaker that's been subject to either scenario.
I think I know what I did wrong. When I went to the image, I copied and pasted the url from the properties of the pic. Instead, I should have clicked the image and gotten the url from that image instead. Sorry.
It's the tuning of the cabinet. The problem is, the driver and cab are designed to work together. If you lower the tuning frequency of the cabinet, the driver may damage itself reaching the lower notes (over excursion).