Adjustable Plug Weld Tool-Seam Style. Use on flush and full length butt weld edges without burn through. Use to back up the weld area on thin gauge materials. For metal panels only! Use with Mig, TIG and Oxy/Fuel welding methods.    Fillers rod 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 welding. The copper pad is 2.5" in length and can quickly be positioned to the next area. Backed by limited lifetime warranty.