I looked for reviews regarding these CDs before purchasing, but there weren't many of them and they were all quite contradictory. I made the broad decision to take a gamble. directly from the factory on order. To get to the point, I visited them for six years, and I have nothing but nice things to say. I flew into the pits several times, causing the entire building to tremble. However, nothing even curved. They were practically perfectly balanced at the time of the initial installation. I would also add that they are really attractive for the price. We have significantly poorer versions of the same pre-owned Japanese ones. I'm completely satisfied with the purchase. I don't know what it's called correctly, but the disk's ornate center line with a logo quickly peeled off, and I didn't particularly enjoy them. They must therefore be glued down right away.