Designed specifically for Shimano’s wireless XTR Di2 system, the BT-DN320 powers the lightning-fast, precision shifts XTR is known for. Housed securely within the rear derailleur, this compact battery is built to stay protected and perform reliably, no matter how rugged the ride. Features: Integrated & Secure: Mounted internally inside the derailleur for protection against impacts and vibration. Reliable Performance: 310mAh capacity delivers long-lasting power for extended days on the trail. Easy Charging: Fully removable design makes recharging simple and hassle-free. Specs: Weight: 22 grams each