<P> A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials . A blade may be made from a flaking stone, such as flint, metal (usually steel), ceramic, or other material . Blades are one of humanity's oldest tools, and continue to be used for combat, food preparation, and other purposes . </P> <P> During food preparation, knives are mainly used for slicing, chopping, and piercing . </P> <P> In combat, a blade may be used to slash or puncture, and may also be thrown or otherwise propelled . The function is to sever a nerve, muscle or tendon fibers, or blood vessel to disable or kill the adversary . Severing a major blood vessel typically leads to death due to exsanguination . Shrapnel causes wounds via the fragments' blade - like nature . </P> <P> Blades may be used to scrape, moving the blade sideways across a surface, as in an ink eraser, rather than along or through a surface . </P>

What is the unique feature of the #12 knife blade