Mitsubishi Pencil Pressurized Ballpoint Pen Refill Power Tank 0.7 SNP7.30 pieces Black refills: 10 pieces, Red refills: 10 pieces, Blue refills: 10 pieces 2700■ The outer box of the ballpoint pen is not included. Shaft diameter 7.95 x total length 111.5mm Black refills: 10 pieces, Red refills: 10 pieces, Blue refills: 10 pieces Oil-based ballpoint pen Ball diameter: 0.7mm Size: Shaft diameter 7.95 x total length 111.5mm [Writes with the power of air] This is a dedicated ink for pressurized ballpoint pens. Compressed air constantly pushes the ink out, allowing you to write on wet paper, in sub-zero temperatures, and even upside down. The micro protrusions on the surface of the spike ball at the tip of the Power Tank ballpoint pen grip the paper firmly, allowing the ink to be written on and grip the paper firmly, so you can write firmly on smooth surfaces such as photographs and drawings.