ABL25,
Dry highlighters are not too common in the US i guess. The ones i have i purchased from Levengers. They are made in Germany. Their catalog now offers a more expensive dry highlighter but probably the pencils are still available. They are sorta thick wooden pencils. I don't use a pencil sharpener because it wastes a lot of the pencil. I use a knife to sharpen it; this gives a nice thick point.
I also bought some from the UK that can be special ordered from Staples.
There's nothing like a dry highlighter for books. Because they are pencil in form, they're light to hold. They also look terrific on paper, i.e., not too bold, just right for the eye.
On the front page you can mark: 1st pass= green; 2nd pass= pink. 3rd pass= yellow. This way, i can tell what i initially grabbed.
Now don't let this confuse you but what i also do is this.... 
if it's real special, i just will go over a color w/ another color & i only do it sparingly. Like a yellow that's really a key point, i'll just go over it in say green.
You see because they are pencils and light & easy to carry around, it's really fun to do. I have dry highlighters that are only a couple inches long now that i put in my pocket.
But the key point for the levenger ones is using a knife to sharpen them & not the sharpener. The ones from Staples are just the opposite; they are very thin. I thought that they wouldn't last long, but, actually, they do. The Staples ones from the UK have more colors: blue, orange & red which is sorta close to the pink.
I bet noone thought i could write so much about my use of dry highlighters 
MM= mind mapping.
