Bell inequalities are an important tool in device-independent quantum information processing because their violation can serve as a certificate of relevant quantum properties. Probably the best known example of a Bell inequality is due to Clauser. Horne. Shimony and Holt (CHSH). https://www.roneverhart.com/Air-Jordan-12-Retro-Nubuck-GS-Black-White-University-Blue-153265-018/