Chroma # 800 Medium Grit whetstone Medium stone use for everyday sharpening. Easy to learn and a must for best results when sharpening Japanese style knives. 800 grit ceramic block rests on raised base for easy use Position each side of blade at 15-20 degree angle during sharpening Professionals sharpen knives often; hobby chefs, once every 6 month Not for use on serrated blades; made in Japan; instructions included