Ⓐ Front & back: Lightweight impact-absorbing material as main structure.
Ⓑ Side wall: Lightweight impact-absorbing material + high density foam to deflect side impact.
Ⓒ Head & bottom: lightweight impact-absorbing material + high density foam + HDPE panel act as a cage that prevents from crushing.
Ⓓ Bottom pad: Absorb vertical impact, can also be adjusted according to the position of the strap pin.
Ⓔ Adjustable Dual Neck Brace system: Bottom brace is adjustable to secure the whole neck from rear and side impact.
This thing is incredibly strong and versatile. I use it every day on public transport and it protects my bass to the point where I don't have to think about it anymore. Did the trick for me. Though notice that if you have a heavier bass like me (9.4lbs) that the waxed canvas khaki weighs a bit more than the rest.