This jacket is made of 13.5 oz. original authentic denim with gray yarn (#7 warp and #6 weft), woven on old G3 loom. Vintage Levi's 2nd jacket has a side seam that only existed in the large size. The back of the flap is made of light ounce chambray to reduce thickness. The stitching color scheme and threads are different for each part. The silhouette of this jacket has been reconstructed to become a new standard.