Features:Magic adhesive patch bottom, available pasted flocking sandpaper sheet, wool ball. 100mm and 125mm two backing pad for your choice, meet your different needs.Adopting universal M8 fastening thread, easy to install.Can be used in pneumatic or electric polishing machine, suitable for all kinds of adhesive type sandpaper.Widely used for artificial stone, furniture, wood products, metals, automobiles grinding and polishing, etc.Specification:Material: PU Foam & Hard PlasticWeight: Approx. 100g/3.5ozThread: M8Diameter: 100mm/4inch; 125mm/5inch (Optional)Operating method: 1. Remove the black rubber thread protective cover. 2. Fixed grinding machine chassis 3. Tighten the grinding pad tightly. 4. Use suede sandpaper to stick to the magic paste. Package List:1 x Polishing Backing Pad