Clinical Electrotherapy - Mettler, Sonicator 740 Ultrasound Device, dual frequency 1&3MHz, 5 cm2 applicator : The Sonicator 740 is 1 and 3 MHz therapeutic ultrasound unit that comes with a 5 cm_ dual frequency applicator. It is light-weight and portable and features a universal applicator cable to make changing applicators quick and easy.