Shimano BT-DN320A Battery – On Component Type 1st Group. Full wireless technology means an all-new Battery. The BT-DN320 fits snuggly and protected within the new Wireless XTR Rear Derailleur and powers the fast and smooth shifting XTR is known for.

• Protected Battery is tucked safely inside an enclosed space so the battery wont budge even in rough terrain while remaining completely removable for charging
• 310 MaH provides for more riding on one charge
• Charger sold separately