a powerfull sword with lightning force to attack, when you use this sword you’ll be able to move by your self to defence or attack automaticly. (used by minamoto musashi (Doraemon and nobita give it to him in the short story)
In the future humans don’t need a diving suit, because it’s too primitive. In the beginning of 22nd Century, human begin to travel across the solar system, and all the planets have diffrent condition and pressure, so this is a light to help humans to adapt to the pressure much faster, no matter how high or low the pressure is. Just light your body with this and you’ll be able to adapt in all condition, the effect only last 24 hours.
Inflateable tent with pump, with 6 private room and eqquipped with a hall / livingroom to live underwater, if you want to use the toilet you have to drain it first. it also have a coocing device to create any food of your choice processed from plankton, a small bacteria living in the sea, not ontil 22nd century that the scientist figured how to use them for food.