These 4-1/2 in. 40-Grit Jumbo Zirconia Type 29 Flap Discs are designed for heavy-duty grinding, weld leveling, blending and surface preparation on metal. The high-density 90-flap design provides more abrasive material than standard flap discs to support longer use and efficient stock removal. Zirconia abrasive grain helps maintain cutting performance during demanding applications, while the beveled Type 29 profile provides a better working angle for aggressive edge and contour grinding. Each disc fits angle grinders with a 7/8 in. arbor and features reinforced fiberglass backing to help reduce vibration and improve stability. This 10-pack is suitable for metal fabrication, automotive repair, rust removal and general shop grinding tasks.