So as far as I know there is an unresolved question as to whether the BeFree filter could get damaged by back flushing. If they don't include backflushing instructions simply because they don't provide hardware for it, then it is pretty easy to jerry rig a system. The cheap plastic cap on the BeFree unscrews and the Sawyer adapter fits the threads. From there you can run a hose to another bottle to backflush. Again... this is all predicated on the assumption that backflushing will not damage the BeFree filter. I've heard mixed positions from Katadyn themselves, so it is not clear to me.