Plus Fours are a type of golf clothing that were popular in the early 1900s. They are a type of baggy knickers that extend four inches below the knee, hence the name "plus fours." They were typically made of wool or tweed, which allowed for greater flexibility and ease of movement during the game. Plus fours were often paired with long socks and a collared shirt, creating a traditional golf outfit that is still recognizable today. While they are not commonly worn anymore, they remain an iconic piece of golf fashion history.