Boosters are used to process difficult applications. When connected between the converter and the probe, the booster (also called amplitude transformer) acts as a mechanical amplifier that increases the amplitude of vibration at the probe tip. Do not use with a microtip, extender, dual probe, or high gain probe. Connecting stud 1/2 - 20.** Length: 5" (129 mm) Part No. BHNVC15. Increases the amplitude by a factor of 11/2.