Was reading the manual on my new truck and saw this, can't beat free if you need a seat belt extender.

 

Are inflatable seat belts used in the unlikely event of a water landing?

 

By law, all dealerships must give you a seat belt extender if requested.

 

Inflatable seat belts are only in the rear seats and are great for protecting older, children. ones in boosters or can wear the vehicle seat belts, supposedly there are only a few car seats that are compatible with them. They actually came out of the aircraft industry as far as I know, that is where I first saw them.
The Ford inflatable seat belt: How it affects car seats and children

 

I've tried to get a seat belt extender for the back seat of my 2017 F-250 CC and Ford doesn't have any yet, they don't even have a part number