Zebra 4C-0.7 Ballpoint Pen Refill - D1 - 0.7 mm - Black

I gotta counter the above review here. I am an illustrator that does a fair bit of product design on the side, and LOVE the fact it is like a standard bic [if a bit smoother and cleaner]. For .7 the line is still pretty thin and surgical which could be the only downside.., but fact is, you can really control the opacity of the line from this, and it lays down smooth & unbroken strokes...which makes it perfect for industrial designers. Needless to say I highly recommend this refill.

I would highly recommend that if you are considering purchasing ballpoint pen refills for your Sharbo X, you should stop for a moment and consider what you'll be using it for.

If you need something that dries quick on any surface, then this may be your best option. However, in my opinion, the quality of line and smoothness of writing is on par with a run-of-the-mill bic pen. I stocked up on 3 pens worth of ballpoint refills and was shocked at how average they write.

If you want to lay down richer, more saturated lines, with smoother strokes, go with the gel refills. I have tried the 0.7s and and they are wonderful.