The rigid foam sanding blocks are coated with flexible diamond grinding material.
They are used for de-burring, to break edges and to grind small areas of materials like
metall, glas, ceramic, carbide, coatings, reinforced plastic and other hard to process
materials as well as to remove leftovers from injecting and spots from casting
on rubber and plastic parts.
Basically grinding tools should be used with coolant (water).

The ergonomically shaped grinding blocks are colourized according to the grit size.

For even areas and edges

Grit 3M: grit 40
equals conventional grit type: 360 - 400