Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Yaxell Tsuchimon Chef Knife, 10-inch
Product description: An example of unsurpassed quality and workmanship is offered here with this Yaxell Tsuchimon Chef Knife. Extremely sharp, extremely hard and extremely durable, these are the ultimate in superior quality kitchen knives. Two hammered layers of high carbon hard steel surround a VG 10 core to form a blade that is not only razor sharp, but beautiful too. These blades have a Rockwell hardness of 61 to ensure that the razor sharp edge is held for a long period of time. The handle is constructed of FDA-approved black canvas-micarta, imported from Spain. This is an odorless, enormously durable material made of resin and linen that will last decades. The end of the each is stainless steel, which gives the knife outstanding stability. Two stainless steel rivets fasten the handle tightly. Manufacturer recommends Yaxell Tsuchimon knives be sharpened with the Yaxell sharpener, a Japanese water stone or a diamond steel honed for sharpening. All Yaxell merchandise is fully guaranteed against defects in material and/or craftsmanship. Yaxell - combining the best of advanced technology with unsurpassed Japanese blade knowledge and expertise handed down from generation to generation for centuries. Made in Japan since 1932. Dishwasher safe.
Product feature: Extremely sharp, extremely hard and extremely durable, Rockwell hardness of 61, Handwash only, Sharpen with the Yaxell sharpener, a Japanese water stone or a diamond steel honed for sharpening, Warranty: All Ginkgo products are fully guaranteed against defects in materials and workmanship
Product price: $139.95
Product brand: Ginkgo International
Target attributes: Set Size
Answer: attribute: set size
value: None
source: None