Bosch Pro 4" 100mm M10 Backing Pad for Angle Grinder Bosch AccessoriesBosch Pro Model 2608601046 4" (100mm) Backing Pad for Angle Grinder M10 Bore Size Diameter Compatible with M10 4" Angle Grinder Fine grinding with an angle grinder requires a backing pad thats durable, flexible, and resistant to heat. Like the PRO Backing Pad. We designed the PRO Backing Pad for fine grinding using fibre discs with P60 grit and above. We made it from durable, heat resistant plastic to make sure you can grind your workpieces