Crab Defense, also known as the Crab Shell or Crab Style, is a style of fighting primarily used in boxing. Variations of this style include the Cross-armed Guard and Reverse Cross-armed Guard, as well as the Philly Shell or Michigan Defense. Crab style fighters Floyd Mayweather Jr., Pernell Whitaker, James Toney, Sugar Ray Robinson, Bernard Hopkins and Nicolino Locche are widely considered some of the greatest defensive boxers of all time. Crab style is considered one of the oldest styles in modern boxing, but variations of this defense are used in several martial arts.