sia Abrasives is a Swiss company with OVER 130 years of abrasive experience and knowledge. Itâs one of the worldâs largest suppliers of abrasives. sia manufacturers abrasives for he surface treatment of any type of surface. They choose only the most premium materials and use the latest manufacturing equipment to provide the highest level of constant quality. sia Abrasives manufactures sanding discs, sanding sheets, sanding sponges, and many more. They have a huge variety of series of abrasives made of different materials to fit your sanding needs.