Main characteristics: High efficiency: with high mechanical quality, it can achieve high transfer efficiency between electrical energy and acoustic energy when working at the point of resonance frequency. Large amplitude: after optimal designed by computer, the speed of vibration becomes high and the amplitude of front plate becomes large. High power: under the action of the prestressed bolts , piezoelectric ceramic energy reaches to the utmost. Good heat-resistance : of small resonance impedance, little quantity of heat, can be used in a wide range of temperature with long life and high reliability.