Shimano Ultegra Di2 BT-DN300 Battery Power your electronic Shimano Front and Rear Derailleurs with the Ultegra Di2 BT-DN300 Battery. The Ultegra Di2 BT-DN300 features a built in li-Ion battery that can be stored inside seat tubes or frames and has three SD300 ports. The battery is waterproof and is compatible with the thinner next generation electric wire SD300 and systems after R9250/R8150 series. Features Delivers stable power to Shimano's 12-speed road derailleurs and shifters Built-in Li-Ion battery Can be housed inside seat posts or frames Three SD300 ports Compatible with thinner next generation electric wire SD300 and systems after R9250/R8150 series Waterproof design Shared fixing method with BT-DN110Weight: 52 grams | Shimano | Ultegra Di2 Bt-Dn300 Battery Built-In Type