This is the crystal nail file I have I saw the crystal and glass ones are the best ones for your nails so I got this one from Sallys Beauty supply for about $4.00. Its double sided and in the middle is just glass. This one is the brand ASP I dont know what that stands for. I got this file about a month ago and my nails look and feel the same as they did when I was using my other nail file so im not sure what this is supposed to do for your nails. I do think it takes length off easily and and if you brook part of your nail and need to file it this one works really good for that and to just file you nail. I do like this nail file at first it felt like it wasnt good for your nails but then i got used to it so now I like it.