Double Bottle Adapter is part of the B-RAD(TM) system that allows you to fit 2 bottle cages side-by-side. *Easy to access bottles and out of the way of legs *Easy to install using existing cage mounts on a bike *B-RAD Base component is required; sold separately Compatibility *Requires use of a B-RAD mounting base *Compatible with any bike frame that has 2 standard 64mm spacing bottle cage mounts (most modern frames)