Thanks for the question and thanks for looking. The MB Baby is not for people who like big and thick pens. Unposted it is not usable. Its cap is not screwed, it comes off with a nice twang, however for posting there is a platinum coated part on the upper part of the pen where you screw the cap with just a twist so you don’t damage the resin each time you post the pen, it posts very securely and when posted the pen finds its balance and itself 
Please note how beautifully it goes from thin to thicker in three separate parts. Posted it is 11.5 cm and 31gr, so it becomes a very normal pen, it actually feels hefty and very balanced in ones hand. As I said before it’s piece de resistance is it’s nib, which is springy and is a delight to write with, glides wonderfully on paper. As you may have noted, it has no clip, so it is very easy to just put in your pocket and carry around. It is also a conversation starter as it is very little people often wonder about it. It is very easy to use, inside, it has a spring for keeping the cartridge securely in its place so one does not have to wonder if an accident will happen when carrying around. As you might have guessed I really like the pen 😅. Please let me know if you have any other questions about it.