TLDR; these rock. Great price, smooth gel writing, and clear colors that erase well.I have a traumatic brain injury, and am back in college in my 40’s. In my academic past, pre-brain injury, I could debate style flow while taking notes, with few if any errors. My brain easily kept track of different topics just because. Nowadays I lose letters, switch letters, forget words, clump beginnings of one word with the ends of another, and my short term memory is CRAP. These pens are therefore AMAZING for my note taking, in class and when I’m taking notes from text. When I make a mistake, it is simple to go back and erase, and since the eraser is silicone it doesn’t pull up and leave crumbs, and it doesn’t eat at the paper. These don’t leave trails or shadows when erased, and I can fix the mistake without the smell, mess, or inconvenience of White-Out.Also, when a topic changes in the text, I can change the color of my pen. I do this when writing out flash cards, as well. The content or definition on each card or for each new topic is a different color. It easier to find when I’m looking for a specific topic, for my brain to sort one topic from the next as I’m scanning through visually. It also makes it one more way for my brain to sort the material as I work to memorize it. I bought Frixion pens first, but in looking for refills that didn’t break my bank, I found Vanstek. Vansteck works as well, costs less, and has many more colors available, too.My ONE caution: don’t use these pens for anything you don’t mind losing. Because they are MEANT to erase with friction, if you leave notes or a journal or planner in a hot car in the summer or in an attic, etc, the content will literally disappear. Same goes for water. These are GREAT on Rocketbooks! But, they also wipe away with water. So if you’re taking notes by the pool, or where a glass of water or other beverage could dump…the paper will dry, but the ink may well have disappeared. So also never use these for something like signing a check or other official document. I even realized recently that I turned two assignments in to an absent minded professor written in this ink, and made sure to go back and let him know to please keep these out of his car and away from beverages, or we’d lose the content of my assignments—and promised never to use these pens to write written assignments that I turned in by hand to him again. Sad for me, but pencil works fine for this particular class, and won’t disappear in a hot car!