The Cisco StackPower cables are thick but flexible, and they carry power as well as a data signal to provide a communications channel among the switches in the power stack. StackPower and XPS cables are keyed and have colored bands on the ends to help you understand what cable plugs into what switch or XPS. A StackPower cable has colors bands on the cable ends, green on one end and yellow on the other end. This cable can be used between Catalyst 3750-X switches and an XPS.