It is a brand. The 50/2 weight is used for piecing. It is a very fine strong cotton that takes up less space in the seam line and makes it easier to get your 1/4 or scant 1/4 seam allowance. It is all I use for quilt piecing. I also like it for machine applique with the buttonhole stitch if I don't want the stitches to show a lot.