The Chef's Choice Hybrid 21 has two stages, sharpening (electric) and honing (manual) for a razor-sharp, arch shaped edge that is stronger and more durable. Uses 100% diamond abrasives in Stages 1 and 2. Diamond abrasive wheels hold shape indefinitely (unlike ceramic wheels which lose shape and effectiveness over time). Diamonds sharpen any alloy. Diamonds are the most durable abrasive, they last and last. Diamond a abrasives will not load up. No need to use messy water or oil. The Criss-Cross sharpening technology offers an extremely sharp edge with lots of "bite". Diamond abrasive wheels sharpen simultaneously into and out of edge for a superior burr-free edge. Razor sharp edges with advanced Hybrid technology, combining electric and manual sharpening. Micron size diamond abrasives in Stage 2 ensure a super sharp polished edge.