Natural whetstone, Nisshozan Hakusuba (white nest stone). The surface was prepared by myself from the raw stone. Please refrain from purchasing if you are looking for perfection, as this is a DIY level effort by an amateur. There is a possibility of layer cracking or chipping, so areas other than the whetting surface have been treated with cashew lacquer. This is a nest stone that easily produces mud and has high abrasive power. It is ideal for removing scratches from medium grit stones. It is a very easy-to-sharpen whetstone, so it is also recommended for beginners. As it is a natural product, there may be streaks or areas that were not apparent during my test sharpening. Please consider this when making your purchase. Length: Maximum 142mm Width: Maximum 80mm Height: Maximum 23mm