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 (included). No additional mount or hardware is required. 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. The Speedfil Z4 is compatible with the Garmin Quarter Turn computer mount. The Z4 integrates a detachable arm which can hold a Quarter Turn Bike Mount to the top of the cage when used in a BTA configuration. This not only saves precious space within the aerobars but also provides easy access. Data is now where it should be – easily viewable and easily accessible. 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. The Z4+ is specifically designed to be used in conjunction with the Speedfil A2. This package includes a non-slip strap that locks your A2 in place and prevents the system from rotating. Also included is a uniquely designed tube clip that secures the drink tube to the side of the bottle and completely out of the wind. This provides the rider with a greater aerodynamic advantage compared to other systems with a fixed mast.