Name: Flap disc Material: Zirconium Oxide diameter: 115mm / 4.5 inch Middle Hole Size: 22mm/ 7/8 inch Option Type: Type-29 40/60/80/100/120 GRIT Designed for grinding, blending and finishing on a wide range of metal Suitable for Stainless Steel also Great for Mild Stee Does this fit the DWE4011? Yes, it will fit. The flap is 4-1/2 "in diameter and the arbor is 7/8" in size, suitable for mostAngle mills. What's the difference between T29 and T27? I often use the T29 disc for derusting and grinding. Because of its flat shape, T27 is suitable for flat polishing. Is it good for wood ? They are ideal for grinding metals, non-ferrous metals, fiberglass, plastics, wood, and other uneven surfaces.