The OS-BASE is an 'over the seat harness' for mounting OS-6, OS-12 or OS-18 ADVENTURE PACKS as soft panniers. A UNIVERSAL-FIT* system for trail, enduro or dual sport bikes with no need for metal frames or racks. The flexible design of the OS-BASE also enables you to mount an extra OS-Adventure Pack or a US-DRYPACK as a tail pack and includes ‘Loop Mounts' to attach a tent or sleeping mat with the addition of OS-Cam Straps or OS-Mini Cam Straps.