XLAB Delta Wing 100 Single Rear Bottle Mount System (Black) Aerodynamic Location  Mounting to the saddle rails in the riders draft allows for clean aerodynamics and easy access. Great way to increase your speed. Stable Design  Strong, sturdy mounting. The material used on the carrier is high strength and will not sway, allowing for fast, safe access to the bottle. SPECIAL CAGE DESIGN  The cage design is funnel shaped allowing for easy insertion of your bottle.