Not sure, but I don't really care because they have a high rating history and are selling them brand new in the box. If something goes terribly wrong and they don't do right by me, I can always contact Amazon. They actually shipped my order within 2 hours.
That is way better than trying to deal with calling the stereo store 2 weeks in advance, having them ordered, driving 3 hours each way to get them, and paying $200 more for the pair. If you live near an authorized dealer, it's no big deal to swing by and get them, but I live out in the sticks and this is the best option for me.