Large stone is made of top-grade silicon carbide. 100 grit on top and 400 grit at the bottom can be used for standard and nitrided table surfaces. Non-slip rubber at the bottom. Ideal for removing damages or welding spatters and maintaining the smooth surface of the welding table. With Base: 7.4″ x 2.2″ x 1.5″ / Stone only: 6″ x 2″ x 1″