Seek Outside add-on Merlin/ Talon bag.  attaches to an SO back pack to be used for compression and/or extra storage.  I got it with my Unaweep 4800 which was also sold on this forum.  The bag has the older style clips as opposed to the newer gatekeepers so it can be used with an older SO pack or the buckles can be cut off to use with the newer style Shoulder straps are removable so it can be used as a Talon just for extra storage  or a day pack- you choose.  Can mail to US or Canada.  Buyer pays postage.