... .Quality Guarantee 3.Best after-sale service 4.Long lifespan In-car Wireless Headphone(SJ-IR2008)Features:Automatic charging protection circuitSuper small ... channel for two car audio sourcesCompatible with car entertainment, PC, TV, DVD, IPOD, MP4/MP3,Auto mute and auto power off Effective range ... ratio: ≥60dB Frequency response: 30 ~ 20,000Hz Channel separation: ≥40dB Power supply: 2 AAA battery