The Bottle Cage Adapter allows for the adjustment of the bottle holder's position either upwards or downwards. When using frame bags and water bottles simultaneously, the threaded holes for the bottle holders present a drawback as they dictate fixed positions, which limits flexibility in space utilization. The Bottle Cage Adapter resolves this issue. On the aluminum rail, the bottle holders can be shifted 55 mm up or down to find the optimal position, ensuring that the frame bag and bottles fit well side by side. It is easily attached to the frame with the supplied bolts and is compatible with both two-bolt and three-bolt bottle holders. An additional benefit is that while there are two holes on the frame, the adapter provides three, allowing for greater capacity for larger bottles. The system works best with bottle holders that allow for lateral removal.