Water stones. Grain size: 150, 360, 500, 1000, 1500, 2000 and 4000 grit. Size 200*70*20mm. Abrasive grain - silicon carbide. Bundle - ceramics. Hardness I ensures minimal wear of the stone during operation. When sharpening does not overheat the steel. Does not require the use of oil. Soak in water for 2-10 minutes before use. Designed for sharpening steels and hard alloys. Made in Russia.