100% cotton. Very comfortable!
Unfortunately, no returns on this product.
I wasn't sure what size to get, so I got an L and an XL. Usually I am a size 7 in underwear. The XL fit pretty good, but the leg holes were a little too large. The L was just right! The back covers my booty well, and the front comes up about halfway to my navel. Good construction, should last for a long time!