In 10 years TF 2 will be 10 years older . <| sep |> That better be some godly broccoli <| sep |> I ' ll go back to wondertrading in a bit , but I ' d like to empty out my inbox before that happens . <| sep |> When you put something that far down and want to get it back , it needs to be able to float . So the ball in this case is a giant bobber and the weights are there to keep it pinned to the sea floor until such time comes when we want it back . The ball is attached to weights via an acoustic lock . It listens for a particular sound and when it hears it , the lock opens and the ball is now untethered and floats its way to the surface . Train wheels bc its cheap and abundant . There are a lot of train wheels at the bottom of the ocean .