Optimize performance of your Spex SamplePrep Freezer/Mill grinders with a wide range of vial sets suitable for your application. Hardened steel vial set offers high durability and efficiency with moderate resistance to abrasion?suitable for general-purpose grinding. Hardness: Mohs 5 ½ - 6; Rockwell ? C 60-65 Typical composition: Major Element ? Fe; Minor Elements ? Cr, Si, Mn, C