"Yellow NWA Zipper Bag hidden in wall of basement. Approximately 3 feet tall with heavy black zipper on top."
"Looks like a ballast bag. Filled with Sand up to 50lb. Usually needed when there are too few passengers on a flight. Those weights are used to balance the overall weight of the flight to optimize fuel usage and prevent catastrophic situations."
...film container. No mine has this particular imprint on the housing. For pressure you install AP or frog type device under, and pressurize with AT.
They are used all over to prevent damage to ships in general.
We use yokohama fenders while repairing the regular fenders on the jetty.