On a hot summer's ride, an extra stash of water or sports drink is never a bad thing to carry. And if your frame only came with one water bottle mount, as is likely if you ride a smaller frame, having two bottles is necessary. The Speedfil Hydration R3 Rear Single Carrier adapts to virtually any rider and bike. Unlike other rear systems which use rigid frames, the R3 uses a movable link design. This allows the cage holder to pivot in two directions so that it is able to fit around the shape of your saddle as well as around your body position. No more pushing back on the bottles when you're climbing, hoping the bracket won't break. You're also able to adjust the position for maximum aerodynamics. This version of the R3 is able to carry a single bottle. It also carries two C02 cartridges, and hook and loop straps secure tubes or tires to the carrier. The Speedfil Hydration R3 Single Carrier is compatible with any saddle, including ISM saddles, without additional hardware.