ADAPTOR SUPORT BIDON ACID BOTTLE CAGE ADAPTER Black When your frame-mount bottle cages are already full, the ACID Bottle Cage Adapter Handlebar is a great way to add extra hydration-carrying capacity. It's compatible with tube diameters of 27.4 – 35.0 mm using the included inserts and can even be mounted on the seatpost with just one bolt adjustment. weight 40 gfits diameters of 27.4 mm – 35.0 mm; suitable for handlebars and seatposts; rotating bottle cage mount; adapter for an additional bottle cagematerial PA6, steel