Giant Propel has an aero seatpost, and neither of three supllied Varia ' adapters' can fit onto it. So I designed and printed my own adapter. : r/bicycling
BMC Timemachine Road adds discs, integrated bar, even race hydration in new aero road bike - Bikerumor
Silverock Alloy Racing Number Plate Mount Road Bike Triathlon Custom Card Bracket Fit Flat Aero Seatpost Vittel Decals - Bicycle Racks - AliExpress