Fine, smooth edge on nails
I've had glass nail files before.  Glass nail files are fragile, so you have to take care of them. These all came in an individual case, which makes taking care of them easier. I have very soft nails, and they split horizonally down in the nailbed.  The smoother my nails are, the better they preform without splitting.  These files work great for fine nails.  I cannot speak for thick nails.
Rating: 5 stars