Liquidraw Technical Drawing Pens For Artists 0.1mm, Refillable

Not quite as well engineered nor as robust – you get what you pay for. Mine broke within weeks, but that could be because the parts are impossibly fine. A 0.1mm pen is quite an engineering challenge - Rotring make it look easy, but it's not. It could be that Liquidraw's 0.3mm and up are better and, with a price tag equal to a disposable, might be worth a try...

This is one pen that is too fine for its own good. When trying to write or draw with it, the nib is so sharp that it cuts through the paper. It's like it doesn't have a nib but a very sharp metal prong. Try writing with a sharp needle and you'll see what I mean, it's exactly like that. The ink by this brand also is not waterproof as advertised, it fouls up your paint. A big shame but it messed up my book really badly.