The new patent pending Speedfil Z4 Cage is the first cage optimized for BTA (Between-The-Arms) aero hydration. The Z4 Cage works with standard water bottles, as well as the Speedfil A2 to offer several unique and distinct advantages. Versatile: The Z4 is lightweight, easily configurable and can be used on any front, frame and rear saddle mounts. Direct Aero Mount: The Speedfil Z4 Cage is designed with numerous ports for a direct BTA mount into the aerobar extensions with a minimum of 4 nylon zip/cable ties. No additional mount or hardware is required. The ports are strategically placed allowing for multiple positions and variable angles accommodating most aerobars.