Standard frame-mounted bottles have high aerodynamic drag, so place your bottle at the rear instead. The Delta Sonic XL mounts on seat posts which have a 10mm horizontal hole at the back. The Delta Sonic XL allows for a rear seat position and is 0.8" longer than the standard Delta Sonic. The rod installs into the seat post for a sturdy, solid system. The system includes a Gorilla XT carbon cage which provides a tight 14-pound grip on your bottle.