Blast Media, 40 Lbs, Corn Cob, 14/20 Grit, Nominal Dia 0.0551 In) Ma, Nominal Dia 0.0236 In) Mi, Nominal Dia Microns Max 1400, Nominal Dia Microns Min 600, US Sieve 18, For Use With Abrasive Blast Finishing Equipment, Used for Cleaning, Deburring, Finishing and Peening Blast MediaFor cleaning, deburring, finishing, and peening applications. Round, smooth media leaves a peen finish. Sharp, jagged media leaves an etched or matte finish. The harder the material, the deeper media will penetrate and the faster it will work. Spherical shape is ideal for use on soft materials where tolerances must be maintained. Contains no free silicas and leaves no residue. Corn Cob AbrasiveBiodegradable organic media removes surface contamination, debris, and coatings with minimal or no damage to the targeted surface. Use on wood and softer surfaces.