Shimano Dura-Ace Di2 internal wiring kits are designed to work only on frames intended to support Di2 internal wiring. This EW-7973-1 kit has a short battery mount meaning it mounts to A Di2 specific battery mount. It internalizes all the wires but the junction box and battery are mounted externally. The external junction box is mounted typically where the BB cable guide is usually located. Please don't hesitate to call with any questions regarding Di2 internal wiring. Questions we will ask will be regarding the location of the battery and juction box.