The reviewers who have expressed skepticism about whether or not these are "one size" are probably right. They fit me nicely at the moment, but if I gained weight, I'm not sure how well they'd fit- they're pretty snug. Also good to note is that the beige color is a lot less yellowy than it is in the picture (which I think is a good thing; it's a nice color in person), but it is also a tad see through. Choose your underwear with caution, or wear a short dress or long top that will cover that area. Otherwise, I like them a lot!