OMG! I have just discovered these awesome sketching tools via the amazing Parka Blogs. The Pentel Aquash brush is a really simple idea - sketchers need water for their brushes while on the move. Instead of them having to carry pots of liquid, why not just build a brush with a reservoir in the handle? Boom!
I have just received a set of three (s, m & l) through the post and tested the biggest. I have to say it seems to work pretty well. The water is drawn into a clear nylon brush tip. Clearly this arrangement is never going to be as accurate as a sable brush, but it seems to do a good enough job. I have just tried it in combination with my water colour pencils and new Moleskine watercolour sketch book and the combo works a treat!
The things are fairly cheap - one will cost about £4, while a pack of three with the various sized brushes set me back about £10. Their build quality isn't great, but I guess at that price they are disposable items anyway. I am mildly worried about how leak-proof the things are, so I'll be keeping mine separate from anything I don't want to get soggy until it proves itself trustworthy. There seem to be more robust versions made by other companies out there, but the Pentel version will do me for the time being.