The Cruz-All Angle Gauge is used to measure Basal Area Forest Stands using 5, 10, 20 or 40 BAF's. The Cruz-All is made of die-cut aluminum with a 25" bead chain with a button at the end. How to use the Cruz-All - Place the button at the end of the chain between your teeth. Pull the chain tight with the Cruz All gauge stretched out in front of you. Look through the Cruz-All and count the trees you see between the opening - at the level of BAF you're using. Cruz-All Gauge CRUZ-ALL$9.95 Need more information? Please feel free to contact us at 1-800-592-6940 - Ask for Extension 547 or Internet Sales.