Claim: A bobby pin is a type of small double-pronged hairpin or clip invented by Luis Marcus and used to to hold hair in place like up-dos, buns, and other hair styles where a sleek look is desired.
Evidence: It is a small double-pronged hair pin or clip that slides into hair with the prongs open and then the flexible prongs close over the hair to hold it in place. A bobby pin (also known as a kirby grip or hair grip in the United Kingdom) is a type of hairpin, usually of metal or plastic, used in coiffure to hold hair in place. In addition to bobbed hair, bobby pins are often used in up-dos, buns, and other hair styles where a sleek look is desired. The bobby pin was invented by Luis Marcus, a San Francisco–based cosmetics manufacturer, after World War I and came into wide use as the hairstyle known as the "bob cut" or "bobbed hair" took hold.