These 3-1/2 Inch X 15-1/2 Inch cloth sanding belts are made with premium German engineered Starcke material. All our belts are made custom to order in grits 24 - 120. This Zirconia abrasive grain features Poly Cotton "X" weight backing. These belts feature a butt joint for a consistent and smooth finish and extended belt life. A full resin bond allows for long lasting performance. This high performance abrasive is excellent for carbon steel and hardwood. Zirconia is also great for tough grinding applications like stainless steel and titanium.