1. The marker pen has a sponge pore hard foam tip, and the ink is oil-based or water-based color ink. Oily ones are usually alcohol solvents and have an odor.

2. The needle pen is a thin steel tube pen tip with a needle inside. The root of the needle is connected to a piece of weight. Normally, the weight presses the needle to seal the thin steel pipe. When in use, the needle contacts the paper surface and the weight is pushed upward, and the ink comes out. In addition, when the ink dries up, if you shake the pen barrel up and down, the weight will also sway, and the ink will flow out naturally. The thickness of the pen tip ranges from 0.2mm to 1.2mm according to the thickness of the steel pipe and needle, and there are many specifications.

3. Signature pens are usually the collective name for fountain pens, ballpoint pens, or disposable water-based pens with hard foam heads. When signing checks abroad, fountain pens are usually used. The pen tip is divided into EF, F, M, B, etc. according to the thickness. EF is the thinnest, and signatures usually use the width of M and B.

4. Differentiation of uses: Water-based markers are used to draw industrial design and interior design plans. I have also seen people use them to draw illustrations. These plan drawings will be outlined with a needle pen or a fountain pen. In the early years, stylus pens were mostly used in architectural drawings and mechanical design drawings, but now that everyone uses CAD, a small number of people who use stylus pen drawings are still playing with it. A signature pen is just for signing, and has little other use. If you don't sign contracts and checks every day, it doesn't make much sense to get a special pen.