1.Hearing aid factory for 9 years 2.N- ... SELLING easy use BTE hearing aid F-137 *AXON,hearing aid factory for 9 years*Mini size ,ligt weight*N-H Switch ... *CE approval*Strict quality control,test by the hearing aid test machine of Fonix 6500-C,Fonix 7000 ... and CR6128 Model:F-137 BTE Hearing AidMax Sound Output:127dB ± 4dBMax Sound Gain:48dB ... AXON HOT-SELLING easy use BTE hearing aid F-137