3M(TM) SandBlaster(TM) Between Coats Sanding Sponges, 20907-180, Fine 180, Sleeved, 2.5-Inch by 3.75-Inch by 1-Inch , 12/cs, Open Stock. The 3M(TM) SandBlaster(TM) Between Coats Sanding Sponge is ideal for preparing freshly coated wood or metal surfaces prior to the next coat.Block sanding sponges are recommended for flat or slightly contoured surfaces. 3M(TM) SandBlaster(TM) coarse sanding sponges cut fast, last long and are clog resistant.