Abstract: An ultrasonic nondestructive testing system and a "sled" for use in such a system are provided for nondestructively inspecting a workpiece. The "sled" includes an ultrasonic search unit effective to radiate or transmit ultrasonic energy in response to a driving signal and to receive ultrasonic energy and produce a received signal corresponding to the incident ultrasonic energy. The sled includes a sealed chamber filled with a liquid couplant. A resilient, elastomeric diaphragm forms one side of the chamber and is adapted to slide along the surface of the workpiece. An ultrasonic search unit projects into the chamber so as to be acoustically coupled to the diaphragm. In addition, an elastomeric member having a high acoustical attenuation and an acoustical impedance corresponding to that of the liquid couplant is provided inside of the chamber for absorbing spurious ultrasonic energy.