This Madworks Sanding Sponge 3mm Combo Pack is Good for Sanding Plastic, Resin, PVC and ABS etc. Especially in Curved Shapes. Durable and flexible, comes with 5 different grits: #320, #400, #600, #800 and #1000. 4 pieces for each grit, for a total of 20 pieces in the package. 20mm x 70mm and 3mm thickness.