It's not a buffing type grit, like on the 4-sided file 'cubes' also sold by Sephora.... One side is effective for truly filing down quickly natural nails that have just gotten too long, or else nails (like those with gel polish on them) that are thick or tough. The other side is not a super fine grit like the pale pink drugstore files you buy for $1.99, but is fine enough that my soft natural nails are easy to shape and finish off in preparation for polishing.
I'd say that you would not want to scrape either side across the top of your nail, but if you have soft nails to hard, it's a good everyday file. By comparison, the glass file from Sephora turns my nails literally to powder... and those brown emergy board files tear my nails up.
For fine nail work, I'd recommend one of the multi-function nail blocks that have fine and ultrafine grits suitable for buffing and polishing the entire nail.
both sides are rough...I was hoping for the typical smooth and rough on normal files. Having said that, I don't really even miss the "fine" side of the file. Weird, I know. The shape makes it more of a precision tool. I haven't over filed once. Oh, and the rough isn't super rough - mildly rough. Hope that helps!