These are light and comfortable,and less visible than other briefs I've tried. For reference, I'm about a size 4, 36" - 37" hip, and I ordered a medium. There may be a teeny bit of extra room but the small may have been a little snug.
These are my new favorite panties. Last year I decided I'm done with thongs for the foreseeable future, yet I don't like the way panties leave visible panty lines and also ride up! The salesperson swore by these, and I'm so glad I gave them a try. I absolutely love them. They're super comfy, wash up well, (although you must hang dry), and the lace edging softens the look of panty lines. Highly recommend.