Hours into a gravel race, the Apidura Aero Frame Module lets oncoming air glide across the center of the bike instead of getting trapped in the front triangle. Transfer panels fill the empty space behind the head tube and downtube, where turbulent air collects and adds drag. Paired with the Aero Top Tube Module, this aero frame bag joins the Apidura Aero System, which saves an average of 5 watts at race speed. What Our Gearhead(R) Experts Are Saying:"My bike has internal cable routing, which the module needs, since external cables near the head tube interfere with the fit. I chose the size from my bike's frame size, not the capacity, and the transfer panels wrapped close around the tubes."