The Massa Model TR-2445/210 is an ultrasonic air transducer that operates in the 210 kHz frequency region. It is encased in a solid plastic housing, which results in a robust package with a completely sealed face. The transducer is typically used in non-contact echo ranging applications where either a single TR-2445/210 is used to first transmit a short duration acoustic signal, and then receives the echo refected from a target; or two separate transducers are used, one to transmit and one to receive. The two curves below show how these transducers operate in these types of echo ranging systems. The System Echo Response Curve shows the typical voltage as a function of frequency produced on the receiving transducer by an echo from a flat target at a distance of 30 cm. The sound pulse was generated by applying a 1 Volt electrical signal to the transmitting drive voltage. The System Directional Response shows the relative reduction in the received voltage produced by the echo as the target rotates to different bearing angles. The maximum system response is at the bearing perpendicular to the face of the transducer.