This specialized Rear End Cap turns any BrightLine Bag into a backpack (with limitations).
This  End Cap has backpack straps built in, but doesn’t look like a backpack  when the straps are not in use.  It's easy to deploy the straps in less  than 20 seconds.  And then it's easy to stow them when you don't need  them.
Now you have the ability to throw your (small) BrightLine  Bag onto your back and use both shoulders to carry the load and be hands  free when necessary.
But there are obvious limitations.  And  because of these unavoidable limitations, we're referring to this as  “The World’s Most Adequate Backpack”.  We do not want people to start  expecting that this new component is going to allow them to replace any  normal backpack they may currently be using. But this new PACK CAP REAR  will make it great for getting down Terminal C hands-free, or from their  car, out across the tarmac to their plane.
The first limitation  is that the BrightLine Bag, to start with, is a pretty short bag.  It’s  only 13.5” tall.  Most backpacks are much taller than that because it’s  pretty far from the top of most people’s shoulders to a place near their  waist line.  So this PACK CAP REAR makes the BrightLine Bag into a very  short backpack.  If you’re tall then the bottom of the bag is going to  hit you pretty high in the middle of your back.  But if you’re a small  person, then this setup will probably work much better.
You will  probably still use the SHOULDER STRAP most of the time, but there are  times where it’s great to be able to whip out the backpack straps and  put your BrightLine Bag onto both shoulders and be hands-free.
The  second limitation is that it really only makes sense to use this new  PACK CAP REAR with narrow configurations like the B0, B2, and B4.   Nothing bigger than that will work.  If you tried to put a B7 FLIGHT  configuration on your back, the length of the bag would cause it to  cantilever away from your back and it would hang down hard and try to  pull you over backwards.  But for the smaller configurations, it’s hard  to beat.