Create flush and full penetration butt welds without the fear of burn-through with this tool. Use to back up the weld area on thin gauge materials. The Mig or Tig fillers metals will not adhere to the copper plate and will eliminate holes. The tool has a magnetic base that can adjust the copper pad to fit securely at the weld area. Simply adhere to the back side and begin stitch welding with the mig gun or tig welding. The copper pad is 2.5"" in length and can quickly be positioned to the next area.Made in the USA.