An ultrasonic flow meter for measuring the flow of a fluid includes a transducer assembly having an adjustable length. The transducer assembly is positioned in a transducer port in the meter body and includes a piezoelectric capsule axially positioned adjacent a first end of the transducer assembly. The piezoelectric capsule includes a transformer, a piezoelectric element axially spaced from the transformer, and axially-extendable wireway. A conductor extends through the extendable wireway and electrically couples the piezoelectric element with the transformer.