What is gas assisted injection molding?
It is conventional injection molding with the addition of a compressed gas (nitrogen) that is injected into the part, forming a hollow core.

Gas assisted injection molding advantages:
Improve polymer flow
Improve product stiffness
Improve surface aesthetics, eliminate sink mark
Reduce internal stress, warpage
Reduce part weight
Reduce number of parts
Can have variable nominal wall thickness
Reduce clamp tonnage

 

It's very good way to make thick parts, like handles etc, where you can't design thin material or use other tricks to make item look thick.
Problem is, that hollow core is very difficult to control. For example I had a fridge with almost 2 meter high door and handle was an ejector. Because children were not careful enough, we had five handles during the eight years of fridges life time. They all were gas filled injection mould parts and there were three different kind of design.

Lesson learned: if you design a Gas filled plastic parts, you really have to know what you are doing.