I cannot recommend this product more. This is an elegant solution to a problem that my d&d group has struggled with for some time - how do we deal with three dimensions in combat? You actually get two helpful solutions here: 1) tracker trees, which allow for three dimensional combat, and 2) cubes, which give height in one inch increments. No more shot glasses, bottles, or whatever else we could find lying around.
This book provides the details to construct tracker trees, as well as some useful printouts. You do need to buy some materials at the hardware store and/or art supply store, and you need to have a little bit of the crafting skill in you. I spent one whole day on the project, and the look on my players faces when I pulled them out was worth the work. I am no longer afraid of three dimensions, in fac6t, I can now embrace them!