Welcome to our srore.Type:Wrist StrapDurable MaterialStylish DesignVersatile UsageGreat ValueSpecial Features: noneMaterial Type: aluminium alloyItem Weight: 340gItem Size: 16*12*5cmColor Name: SilverAudio Sensitivity: none To Noise Ratio: 80dBImpedance: 4-8?Frequency Range (Hz): 20Hz-20KHzOut Power: 20WX2Model Name: Car AudioAudio Encoding: StereoItem Type: AMPLIFIERSCertification: noneattribute: sound amplifier for car,amplified subwoofer for car,amplifier for speakers