@freemo No flex, I'm not really into calligraphy although I certainly wish I had beautiful handwriting. With that said, I love my pen. It's so smooth, I don't have to apply even a touch of pressure. Works well for maths, which in was originally concerned about. Being able to try different inks has made writing a bit more interesting & I've enjoyed it. I've also got a few J. Herbin rollerball pens. They take standard cartridges and are cheap enough to have a few for different colours.

@comphys The two I suggested are stiff enough and fine eough to be good for diagrams and math, but the falcon can give if you are trying to flex it. So it is great for both if you ever just need to sign your signature or somethng.