New belt tension tester from Econobelt uses sound waves instead of force deflection to accurately measure tension. The portable, lightweight and easy-to-use meter produces repeatable results for any operator. It can be used in almost any environment and produce fast results, calculated in seconds. The unit, identified as the 507C runs on four AAA batteries. The Model 507C comes with a cord sensor. Optionally available are an inductive sensor or a flexible sensor, and a cord sensor.