Use: Internal Di2 battery mount.
CYSKY Bike SeatPost Adapter Shim 27.2mm to 28.6mm, 60mm Length Bicycle Seat Post Tube Adapter, Seatpost Reducing Sleeve Shim for Mountain Bike, Road Bike, MTB, BMX
30.9mm To 31.6mm 27.2mm Bicycle Seatpost Sleeve Shim Bike Seat Post Tube Adapter
Bicycle Seatpost Adapter Shim Tube Sleeve Bike Seat Post Reducer Adapter for MTB
Bike Seatpost Alloy Shim for Brompton Folding Bike,Lightweight Bicycle Seat Post Adapter,Reducing Sleeve,Diameter(34.9-31.8)
Bike seatpost reducer shim extension convert tube adapter 27.2 25.4 30.9 31.6
