【Upgraded High-Density】Each flap disc is equipped with 90 abrasive flaps, a 25% increase over the standard 72 flaps found in common market variants. This results in superior grinding efficiency, enhanced durability, and increased density.【Zirconia Oxide Grains】EZARC Flap disc is crafted from premium blue zirconia oxide grains, ensuring strength and durability, extending its lifetime by 50%.【Multi Application】40 grit flap disc is coarser in build and is ideal for heavier stock removal. Our flap disc is widely used for metal or wood, to remove the weld reinforcement, deburring, polishing, and to rust removal.【Convenient to Use 】Bevel Type 29 angle design makes the edge and corner grinding much more convenient, great for surface sanding, and working on welded seams at a working angle of 5 to 15°.【 Professional Grinder Flap Disc 】 4-1/2-inch diameter with a 7/8-inch arbor size compatible with an angle grinder with a maximum 13,300 RPM grinding speed. This angle grinder flap disc is designed for grinding, blending, sanding, and finishing on a wide range of material.