Thin pens comparing / 얇은 펜 비교

One of my favourites is about pens. 

Especially, the charm of a fountain pen. Whenever the tip touches and scratches on different papers and delivers the textures to the fingers, the sensation of the writing comes to different joyful events.   

Yes, most of the time, fingers were stained with ink without noticing, and the ink was dried out without using much. Maybe using a fountain pen is not effective in this fast modern life. I like to keep a journal with me wherever I go, a thin pen is essential to keep track of the limited pages. I know it's  just excuses. I can write with anything I can find in that moment, actually.

Pentel Energel 0.3 is the thinnest, but that line has no option for a colour multi-pen. 
Uni Jeststream 0.38 4-in-1 multipen is the final companion to my journal. 
Also, the Platinum Preppy EF is a seldom-guest.

Anyway, recently, I came across the capless (retractable) fountain pen. 
Already, I have more than enough pens, including fountain pens, because of Amazon and Aliexpress. 

I cannot resist the temptation to have Jinhao 20 and Majohn A10. 

I hope that Jinhao 20, maybe the last fountain pen I bought. But i cannot satisfy about the thickness of the writing as EF tip, and the ineffective airtightness. So I finally bought this Majohn A10. In Amazon, over 60-70$ and Ali, 33-40$. It is much heavier than Jinhao 20, which is plastic, because of the metal housing, but it is well-balanced and writes quite smoothly, even though the EF tip. No case came with 2 cartridges, 1 pipette, and 1 converter included. Definitely, thinner than Jinhao20 EF. I don't have a chance yet to test the airtightness to keep the ink dry.  I'm satisfied for now. 

Still, it spread more on my journal paper, and I cannot use it for that.