Good for use on mild steel for finishing, cleaning up imperfections. A great deal compared to your local store. Buying these in bulk saves you a ton of money. and having a few spares is handy. Use these on aluminum, wood, and rusty metal. It can be installed on electric drill conveniently. Feature - Color: As Shown. - Material: Alumina. - Size: 4.7 x 3 x 3 cm. - Enhanced surface and control: resulting from the angled flaps maximizes the optimal application of pressure to the cutting surface while ensuring ease of use, comfort, and grinder control. - The angled flaps enable the user to hold the angle grinder at a natural, angled positioning while still enabling the disc to maintain with the grinding surface. - Superior durability and value: stems from the alumina material which lasts longer than traditional material ndash; making for a more durable and cost-effective grinding wheel: they simply provide more for less. - Extensive application: Stock removal, grinding, blending, beveling, deburring, removal of rust and paint, finishing, and other similar applications on metals, non-ferrous materials, fiberglass, plastics, woods, and many other surfaces. - choice abrasive: flap discs have quickly become the go-to abrasive disc and are continuing to grow in popularity due to their cooler cutting, less frequent burning and gouging, lower vibration and noise ndash; and ultimately, their superior value.