A holder for an extra bottle cage behind the saddle by clamping the saddle rail.
This position has advantage to aerodynamics to reduce the resistance against head wind. It's good for road race and triathlon.
You can also use this position to carry spare tube too.

Made of steel with anti-rust ED painted finish.
Comes with bottle cage mounting screws

Fits standard saddle rail only. Not compatible with I-Beam saddle.