This is a natural whetstone, an Omura stone. The origin is unknown. It's thin and small, but I think it can be used for small blades. Recommended for those who want to try an Omura stone. As it is a natural product, there may be streaks or areas that pull during sharpening that were not apparent when I tested it. Please consider this as well. Length: Max 144mm Width: Max 70mm Height: Max 13mm