Shimano Di2 e-tube WiresUltegra Di2 wires utilize Shimano's e-tube technology; e-tube is a two-prong system and is NOT cross compatible with Dura-Ace 7970 Di2 wiringAll e-tube wires may be used for internal or external applicationsFrame grommets for E-tube internal-wiring compatible frames are sold separately, see Shimano Frame Grommet Kit Electronic Shifter Extra PartsItem SpecificationsLength650mmFD/Shifter CompatibilityShimano Ultegra Di2,Dura-Ace 9070 Di2 Shimano E-Tube Wires and Connectors E-Tubes, Cables & Extensions UPC: 689228828148