Shimano BMR2S1 Di2 Small External Battery Mount

All Di2 components on the bicycle require the same firmware version. Using Di2 components with different firmware versions may cause malfunctions
Use Di2 system checker to update component firmware from http://e-tubeproject.shimano.com/
For use on frames that have a specific Di2 battery mounting location on the chainstay or down tube
Compatible with both internal and external wiring kits
10mm mounting bolts