Plus fours or plus-fours are breeches or trousers that extend four inches (10 cm) below the knee. Knickerbockers have been traditionally associated with sporting attire since the 1860s. Plus fours were introduced in the 1920s and became popular among sportsmen—particularly golfers and game shooters—because they allowed more freedom of movement than knickerbockers. Less known are plus twos, plus sixes, and plus eights, of similar definitions, but accordingly varying lengths.