The Naniwa Hibiki stones are vitrified aluminum oxide stones designed for precision sharpening. Vitrified means the material has been fused at high temperatures to create a dense, glass-like structure, making it harder and more durable. This makes the Naniwa Hibiki stones particularly hard and flat - ideal for woodworking tools, chisels, plane blades, and high-hardness single bevel knives. This Whetstone is: - Soaking - Requires 10 - 15 minutes of soaking before use for optimal performance. - Fast Cutting - Great for hard, high-alloy steels - Extremely Hard Wearing - Maintains flatness for extended use, reducing the need for frequent resurfacing. - Good Tactile Feedback - You can feel the angle of sharpening easily Available in 4 Grits: 1000 Grit - This stone is 210mm x 70mm x 20mm 3000 Grit - This stone is 206mm x 70mm x 20mm 6000 Grit - This stone is 200mm x 65mm x 20mm 8000 Grit - This stone is 200mm x 65mm x 20mm Notice that the stones are not all exactly the same length and width, although they are all the same thickness. Weight (approximate): 1000 Grit - 610g 3000 Grit - 580g 6000 Grit - 560g 8000 Grit - 540g