双 is used as a measure word for things that come in pairs: 一双鞋 (a pair of shoes), 一双筷子 (a pair of chopsticks), 一双手 (a pair of hands), 一双眼睛 (a pair of eyes).
culture
双 is considered auspicious in Chinese culture because even numbers symbolize togetherness and good fortune. 双喜 (double happiness) is a symbol used at weddings.
