Bag with adjustable size

[Apnea]

Any bags that feature adjustability in terms of volume, other than those that you fill yourself? Some kind of compression accomplished by something other than your hand (snap, cinch strap, zipper, etc) that lets you make one bag work for more situations.

 

[Mr.BR]

I put an inflatable air bag in mine and a pocket for the pump , works ok

 

[Apnea]

I put an inflatable air bag in mine and a pocket for the pump , works ok

Interesting. Any pictures handy?

 

[Mr.BR]

On the small bag i just took out half of the fill and zipered a airbag in , saves 300g in weight and is super comfy to adjust size/height, i am also having one the larger bags modified for the inflatable bag insert