These high density foam blocks have four sides coated with silicon carbide abrasive. Hard wearing and long lasting they are available in a variety of grits. They are a convenient size at 98 x 69 x 26mm, a handy item for sanding off filler or repair compound. The tough silicon carbide abrasive is effective on paint, varnish, lacquer etc. Use these to gently soften edges on unfinished timber. A 120g sponge in available with a trapezoidal cross-section one edge has an acute angle and on a curve. This shaped block is ideal for sanding areas which are difficult to get to and concave profiles.