Need some heavy-duty flap discs for your angle grinder? This 50-pack has you covered. They're 4 1/2 inches in diameter (that's 115mm) with a 7/8 inch arbor hole, so they fit most standard grinders. The grit is 40, which is great for aggressive grinding, blending, and finishing on tough materials like metal, stainless steel, and even wood. They're made from calcined alumina, which is a step up from regular aluminum oxide – it's more durable, wears slower, and cuts cleaner with less noise. Whether you're a pro welder cleaning up beads or a DIYer working on a project, these discs are a solid value in bulk. The T29 shape (flat with a depressed center) works well for surface grinding. Grab this pack and you won't need to buy discs for a while. Just remember to use proper safety gear!