In case you have seen me walking miles with backpack, here is how you can too with broken spine that is

INTERIOR IS MADE OUT OF ALUMINUM WITH HOLES DRILLED IN ONE FOR SEWING PURPOSES.

Enough to carry small laptop with me.

Its a life saver in environment as I am in. Without fresh air, I wouldn't last long in environment as they designed.

Make sure its center positioned and straight - horizontal with backpack edge(parallel) as you don't want pain in spine - any irregular unstraight movement can deteriorate your spine issues instead and not solve them, so you must pay very close attention to work.

Parallel with backpack as you see and in center.

It used to be 15 to 20kg with zero pain unlimited - its now 2kg for even up to half day, but with half pain of what it used to be without seen here.