CATWALK ORIGINAL Smart Mini Keychain Pens - Compact Pocket-Sized Writing Pens for Nurses, Students & Professionals - Includes 3 Ink Refills - Perfect for Notes, Medical Charts & Daily Use - Stylish Unique Patterns

I read all the reviews talking about how small these were, and still found these to be even smaller than I expected when I received them. Provided is a size comparison between one of these and a normal size everyday pen. However, I do find them comfortable in my small woman hands, especially with the weight they have. They write nicely with blue ballpoint ink. The point comes out by a twisting mechanism, but it doesn't click into place when twisted out. This might be fine, provided you don't twist the pen in your hand while writing. I don't think I will have problems with this based on how I hold it.To open them for refilling, you just pull the top half of the pen from the bottom half, and with some resistance (good) it will come apart. The ink cartridge is metal with a plastic cap on the end, which twists into its housing. The cartridge is 55mm long and about 2mm thick, which makes them smaller than D1, so proprietary refills will be necessary. That is probably the one main negative I have for these.I also feel they're overpriced for what they are (mostly because of their size), but compared to more expensive EDC keyring pens online, these are better designed for my needs (easy to unclip from my ring with the lobster clasp, no chance of losing it due to failing magnets/unscrewing itself, etc). Finally, the pattern appears to be paper wrapped around the metal, making it likely to scratch off over time. I'm not concerned by this, but people who care about their pens being photogenic might. I think these are high quality regardless.