The Shimano SM-BCR2 E-Tube Internal Battery Charger is designed specifically for charging Shimano Internal Di2 batteries. This charger is compatible with E-Tube equipped bicycles that have an internal battery setup. With the included USB (SM-USB1) power adapter, you can conveniently charge your battery. Keep your Di2 system powered up and ready to go with the Shimano SM-BCR2 E-Tube Internal Battery Charger.