Materials：Aluminum Oxide This series of grinding discs are installed in theangle grinders and are suitable for long-last& heavy grinding. They are also used to grindwelded seam, welded spot, casting burrs and torepair metal surface’s defects in the fields ofautomotive, ship building, machinery,metallurgyetc. This series of discs are with 3 fiberglass nets andthey pass German MPA certification.