I think it would be wise if anyone purchased these files in the black case and hasen't yet tried them, to do so now as I think that reading the reviews there might have been a faulty batch ! I already had the LD files in the white case and think they are great, so bought these as a present to give to a friend next month,so obviously hadn't tried these. Some reviewers are saying that they are basically smooth and don't file!! I have just tried mine and sure enough they don't work, plus as one reviewer says, the marks on the files then don't come off when washed under the tap, as the white set do. My set are going back for a full refund and I think QVC should admit that these files may be faulty, nevermind saying the case was leather on the website, now changed because somebody must have complained.