For seat post ID24.5mm to 28mm or ID20mm to 23mm*Battery and cable not included*
Pro Di2 Seatpost Battery Mount For Sm-btr2 For 30.9 - 31.6mm seatpost
M:part Di2 Seatpost Battery Mount Internal Post Diameter 20mm to 23mm
Shimano Sm-bcr2 Di2 Internal Battery Charger Direct To Sm-ew90 Junction
Giant Internal Seatpost Di2 Battery Holder
Pro Discover Seatpost Carbon 31.6mm x 400mm 20mm Layback Di2
