Output SPL: ≥88± 3 dB SPL /1V/0.1M at  2.0K Hz，in 1cc box

 Resonance Frequency (F0)：650±20%Hz950±20%Hz while testing in 1cc box

 Frequency Range ：F0~20kHz.

 Rated Impedance ：6Ω±15% (@ 2KHz 1V)

 Magnet：Rare earth permanent (NdFeB) magnet   

 Distortion：Less than 15% 1KHz input1V，in 1cc box.

 Buzz, Rattle, etc.：Must be free audible noise (buzzes and rattles)( 400Hz ~ 5KHz frequency range ,input level up to 2.0Vrms, while testing in 1cc box.)