An oil-based ballpoint pen that eliminates the weak points of the previous ballpoint pen; The Power Tank is a characteristic of the Mitsubishi pencil ball pen uni series. This ballpoint pen features approximately 3,000 pha compressed air that allows you to write with the pressurized ballpoint pen ink that is pressurized using a method of pushing out. This is an excellent product that eliminates the weaknesses of previous ballpoint pens that reduce interruptions and stiffness when writing.