Bases are the foundation for the B-RAD System. Reposition water bottle cages to optimize the position of your water bottle when using bags or to optimize fit on smaller frames. Lightweight, durable, rust proof materials. Mounting any of the bases requires the use of at least 2 standard threaded bottle cage mounts. B-RAD 3 and 4 should use the auxiliary foam pad (to protect your frame) and zip tie to secure the base. Any other mounting methods are not recommended You may need a Problem Solvers Space Out Kit or similar method to clear the front derailleur clamp. Be sure to use bolts with additional length equivalent to the extra spacing added Compatible with any frame that uses standard 64mm spacing bottle cage braze-ons (basically every modern frame) Hardware included is T25 Torx head