The very latest tree height gauge is designed to assist an arborist in taking accurate information about the height and lean of a tree. The Cross Sight is a pocket sized height measuring gauge that you rests on the bridge of your nose. Measurements are made using the age old technique of equal sided triangulation with one corner of the triangle being your eye. Side lean, back lean and lift calculations can all be determined with the Cross Sight. The easy to use charts printed on the sides of the Cross Sight are designed to perform quick calculations in the field.