Shimano Di2 Seatpost Battery Holder (For 27.2 - 28.6mm Seatposts) - PRAC0094
Shimano Di2 Seatpost Battery Holder (For 27.2 - 28.6mm Seatposts) - PRAC0094, The Pro Di2 Seatpost Battery Holder mounts a Shimano Di2 internal battery into 27.2 - 28.6mm seatposts or frame tubes.