The Topeak Backloader Wishbone attaches to the saddle, and provides anti-sway for large saddle bags. In addition, the Wishbone has bottle cage mounts to allow 2 additional bottles to be carried. A handy accessory to add to your bikepacking repertoire that keeps the backloader or any large seat bag from swaying back and forth. - Fits rear bags 18cm/7" wide - Bottle cage bolts included, max load 4.4lbs - Mounts to any standard seat rails. Not compatible with monorail or spring/bumper saddles