By using the Timber Tester, you can determine the best timber to use for the most critical members of the bridge or tower as well as the optimum way to orient the timbers to provide the maximum amount of load-bearing capacity for any structure. The unit is durable, with the main member of the unit constructed of rugged ABS plastic. The testing span is adjustable from 4 to 12 inches, and the scale provides readings from 0 to 7 units of load. We recommend one Timber Tester for every four to six “structural engineers.”