A bottle cage is device used to affix a water bottle to a bicycle. Composed of plastic, aluminum, stainless steel, titanium or carbon fiber, it is attached to the main frame of a bicycle, the handlebars, or behind the saddle. Most modern bicycles have threaded holes in the frame to hold the bottle cage, often called braze-ons even though they may be welded, glued, riveted, or moulded into the frame material. The most common location for a frame-mounted bottle cage is on the top side of the downtube. The most common location for a second frame-mounted bottle cage is on the front side of the seat tube. Small bikes and mountain bikes with rear suspension often do not have enough room for two bottle cages inside the main frame triangle. Bottle cages can also be mounted behind the seat with a bracket that attaches to the seatpost