Favorite Map Scale Tool?

What is your favorite type of Scale Tool: Grid, Slot, Corner or Roamer?

heh i didn't know the names, but this is the one i like
http://cache.backpackinglight.com/ba...tCorners-M.gif

i couldn't say why really but i never liked the 'slot' other than i like to use grease pencils on waterproof maps and they never fit in the slots, so i wind up using outside edge anyway

I prefer the Forestry Suppliers UTM Grid Reader II.

Pictorial/terminology ref.
https://www.maptools.com/utm_tools

Not to be a dink, but it's "romer" not "roamer"...

I stumbled on this thing ... looks kinda big 4x7. Not sure what style it falls under.

http://www.campingsurvival.com/bralmaptopro.html

I personally like the grid tool. The reason I like them is they normally have an integrated protractor. My gripe with most of them is when you fold up most maps it seems like the scale is always slightly larger than the map. Making this worse is that most of my map books fit the maps perfectly. This creates the problem of trying to figure out what to do with the scale.

Hopefully you are thinking of making a better map protractor/scale.

FWIW, I perfer UTM