If there is no space for the universal Rotlicht holder or the seat-rail holder because of a saddle bag, you can simply attach your red light via the backpack mount to the saddlebag itself. So even if you are simply not on a bike, you can affix the red light directly to your backpack, ball cap, etc. for maximum pedestrian safety!
About the ROTLICHT:
The Lupine ROTLICHT, German for 'red light,' is not only bright in front of you, but also behind you. With incredible 160 Lumens of red light output, this is probably the most powerful tail light with integrated battery.