| http://www.w3.org/ns/prov#value | - 20110304256SPARK PLUG AND MANUFACTURING METHOD THEREOF - A spark plug including a center electrode; an insulator; and a metal shell, the metal shell including: a tool engaging section; a body section; and a groove section formed between the tool engaging section and the body section, and having bulges which bulge in an outer peripheral direction and in an inner peripheral direction.
|
