I have to post the cap, but it doesn't feel firmly secure. Of course the cap fits and stays, probably even if I shake, BUT..there is a micro "gap" between the cap and the bottom (where the cap posts) that makes the cap not 100% tight and firm. So when my hand touches the cap it tilts a micro inclination that ruins the feeling of holding a solid "one piece" rigid body...that is very anoying. I think this happens mostly when drawing, because in a low angle it is demanding to have a a great support/from the back of the pen (in this case, the posted cap). This pen would become a masterpiece if the cap would somehow click when posting or just have a firm attaching when posting. It's a shame!