I got these sheets for my sons bed and they fit his mattress perfectly. The corners are snug enough that they do not slip off easily, even for a kid who tosses and turns a lot in his sleep. But they are not so snug that it's almost impossible to get the sheet on. They are soft and comfortable. Very light. I did get the twin fitted sheet and it fits very well on his twin sized bed. They are machine washable and 100% cotton. If you are looking for a new set of sheets, I recommend the Color Sense brand.