Multi-use Item

I found it most interesting on Friday when our son called from the other side of the world that when I described this to him, he knew exactly what it was...

He even told me the approximate size of it...  He said it was just like they stored water in for showers in Iraq when he was there just a few years ago.  He also said that when he saw the Special Ops guys "sunbathing" on it in their shorts, he decided, "I'm going to be one of those guys!"  And now he is....