This is used to measure the deflection of a flexible pavement under moving wheel loads. In use, the probe is placed between the tires of a test vehicle, and deflection is measured as the vehicle passes over the test area to beyond the end of the probe beam. The reference beam is equipped with a leveling adjustment to zero the dial indicator. A switchable battery operated vibrator serves as a personnel alert and assures free movement of beam parts during measurements. Unit comes with chrome plated 3-piece beam, 20 x 0.01 mm dial indicator and four D-cell batteries for the vibrator. Order optional carrying case separately.