RIKON’s PROseries 8″ sharpening wheels features CBN (Cubic Boron Nitride) abrasives, one of the hardest materials besides diamond! Mounted on your grinder, these wheels will put razor sharp edges on your hardened steel tools – woodturning and carving gouges, chisels, plane blades and other cutting instruments. Each sharpening wheel is precision machined from solid aluminum, balanced, and bonded with fine CBN abrasives that are ideal for sharpening hardened heat-treated steel tools. CBN wheels cut quickly with minimum pressure, stay cool and never needs dressing or shaping. Wheels fit onto grinders with 5/8″ shafts and work best on low-speed grinders operating below 2,000 RPM. Note that CBN wheels are not for use with soft carbon steel, aluminum or other soft metals which will ruin the abrasives and void the warranty. Stones are packed in cardboard boxes for safe storage and transporting.