The manufacturer’s double-disc grinders use two 10- or 20-segment, 10-in.-diameter diamond grinding discs to level, smooth, or clean the surface of concrete slabs. Counter rotating discs provide balanced torque to prevent pulling left or right. Use the machine to level small areas of uneven joints or high spots of 1/16- or 1/8-in. A dust shroud contains grinding debris. MK Diamond Products. 800-421-5830.