Oil Palm Harvest Knive Sharpening Stone available in 621-B 6" x2" x1" Black Silicon Carbide 821-B 8" x2" x1" Black Silicon Carbide 832-B 8" x3" x2" Black Silicon Carbide 621-G 6" x2" x1" Green Silicon Carbide 821-G 8" x2" x1" Green Silicon Carbide 832-G 8" x3" x2" Green Silicon Carbide