This brief has one seam going up the back. I started buying them many years ago because they fit so smoothly. Unfortunately, the type of fabric used today seems thinner, the elastic is not top quality and the stitching is not always well done. I have had to sew up tears and secure edges along the waistline many times. The latest shipment ran small in comparison to those I already own in the same size.  I am in the market for a similar panty without these problems.