These replacement cleaning and polishing pads are available in two different sizes to fit the Old and New models of billiard ball cleaning units. The Old model pads have a diameter of 9 inches, while the New model pads have a diameter of 8 inches. If you're unsure which size you need to purchase, you can use a measuring stick or ruler to determine the diameter of your existing pad. Simply measure the length across the pad to determine the correct size for your unit.