The Pentel Brush Sign Pen Pigment is a variation of the Pentel Sign pen which uses water-soluble ink. As the name suggest, the ink is pigmented, hence waterproof and fade-proof.
The Pentel Touch uses the brush tip. Pentel Sign uses the bullet tip. Pentel Brush Sign Pen Pigment uses a (small) brush tip.
The brush tip allows you to create thin and thick lines depending on the pressure you apply, or how you hold the pen.
By default, the lines are quite thick, probably a B line if you compare to fountain pen nibs.
Here's a sketch drawn with the pen and painted with watercolour.
The pigmented ink is waterproof. Doesn't smear or feather.
This sketch was coloured with alcohol based marker.
I'm not sure how long the ink can last but this pen can be refilled. The end cap can be removed to reveal the sponge inside. I'll probably use Rotring ink for refill because it's more fluid and don't dry with crusty ink particles.
The ink performs really well. Ink flow is good. Overall it's a fantastic pen. This is good for people who want to draw thicker lines.
You can find this pen and more reviews at Dick Blick (USA)