USB Line Out Dock Cable lets you get high-quality line out audio from the dock connector of your iPad/ iPhone/ iPod while charging. One end has a 30-pin connector that attaches to the bottom of your iPad/ iPhone/ iPod and the end other splits into a 1/8(3.5mm) stereo audio plug and a standard USB connector. Plug the audio into a home/ portable/ car stereo to listen to high quality line-out audio. Plug the USB into a computer or wall charger to charge the iPad/ iPhone/ iPod while listening for hours. Connect your iPod or iPhone to car audio or amplified speaker with aux input. The dock connector sends line level audio out from your iPod / iPhone and provides a better sound quality then the headphone jack output. Cable is 12" in length.