Note: This item only fits 31.6mm 3T Seatposts.
Material: Stainless steel (lip); AL-alloy (body)
Weight: 12 g
Battery Holder locates a Shimano Di2 seat-tube-fit battery(Shimano SM-BTR2) inside a 3T seatpost, enabling easy fitting and removal of the battery. It is compatible only with 31.6 diameter seatposts.