Enduristan Sandstorm Extra Fastening Buckles If you have two bikes and intend to use Sandstorm bags on both, you will require an additional pair of rear fastening buckles for the second bike. However, if you only have one bike, you do not need this accessory as one set of rear fastening buckles is already provided within the Sandstorm bags' package. Compatibility: Sandstorm 4A Sandstorm 4E Sandstorm 4H Sandstorm 4S Sandstorm 4X Sandstorm 2E Sandstorm 2S Sandstorm 2