Every Beauty 3-in-1 nail file, $5; everybeautybrand.com.The Claim: If you're coveting Rihanna's stiletto tips, this is the tool for you. The curved shape of the stainless-steel file glides effortlessly around the edges of nails to form any shape, from square to almond, in seconds.
Expert Opinion: "I've never seen anything like it," says N.Y.C. manicurist Dawn Sterling. "A lot of women have a hard time crafting oval shapes with a straight file, but this makes it easy. And you can work it around long or short nails." Diagrams on the back of the package will help you get started.
Our Take: It's 50/50. One tester finds it "comfortable to hold" and says, "I ran the corners of my nail over the length of the file and had a rounded tip in less than a minute." Another found it harder to handle, saying, "I'm much faster with my regular file."Read MoreLess