A tri-frequency probe emits three different frequencies. Probes with tri-frequency capabilities allow a wide range of scanning applications from a single probe.

See also Multi-Frequency Probe and Dual Frequency Phased Array Transducer.

Usually, multiple probes are used because most transducers are only able to emit one frequency because the piezoelectric ceramic or crystals within it have a certain inherent frequency.
Multi-frequency probes have multiple crystals with different frequencies and the desired specific frequency can be selected. Advanced probes can emit sound waves at different frequencies for the near and far fields. The disadvantage is that multi-frequency (multifrequency) probes have slower frame rates and therefore they are only useful for imaging of static structures.

See also Dual Frequency Phased Array Transducer and Tri-Frequency Probe.

From SIUI Inc.;
'A breakthrough in traditional designation
The latest technologies and processes
Closely combined with up-to-date IT technology
A variety of advanced ultrasound imaging technologies
The best solution provided for users'

'CTS-5000 can match a variety of super high density, super broadband, multi-frequency probes, including convex, micro-convex, linear, vaginal, rectal probes etc., which are widely used to different clinical diagnosis such as abdominal (liver, kidney, gall-bladder, pancreas), gynecology (uterus, ovary), obstetrics (early pregnancy, basic obstetrics, multi gestation, fetal echo), cardiology (adult and pediatric cardiology), small parts (thyroid, galactophore, testicles), peripheral vascular, prostate.'

From SIUI Inc.;
'CTS-415 PLUS is a premium digital B/W ultrasound system with outstanding images and powerful application functions. It meets all your clinical requirements on black and white ultrasound examinations.'
'A variety of probes including convex, micro-convex, linear, vaginal, rectal probes and powerful imaging functions enable wide applications in cardiology, abdomen, small parts, pediatrics and OB/GYN.'

From SIUI Inc.;
'Dedicated to ultrasound industry, Shantou Institute of Ultrasonic Instruments, Inc. (SIUI) has launched Apogee 3500, the Digital Color Doppler Ultrasound Imaging System.
With latest imaging technologies, high-definition image quality and excellent practical functions, the Apogee 3500 offers optimal solutions for clinical ultrasonic examination.'

'The Apogee 3500 is available with many high-density, super broadband and multi-frequency probes, such as convex, micro-convex, linear, vaginal, rectal and phased array probes, which are widely applied for different clinical diagnoses, including abdomen (liver, kidney, gall-bladder, pancreas), gynecology (uterus, ovary), obstetrics (early pregnancy, basic OB, complete OB, multi gestation, fetal echo), cardiology (adult and pediatric cardiology), small parts (thyroid, galactophore, testicles, neonate), peripheral vascular and prostate.'