Shimano E-Tube wiresAll 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 PartsUltegra Di2 wires utilize Shimanos e-tube technology; e-tube is a two-prong system and is NOT cross compatible with Dura-Ace 7970 Di2 wiringItem SpecificationsGenre850FD/Shifter CompatibilityDura-Ace 9070 Di2FD/Shifter CompatibilityShimano Ultegra Di2