This 3.5mm TRRS to XLR cable allows you to connect a pro XLR mic to your iPhone®, iPod® or Blackberry and take advantage of the many apps designed for audio recording on a Smartphone. Using external microphones will improve the quality of your recordings. Built with phantom power blocking and impedance matching components. This cable also features a headphone monitoring tap for critical applications such as field reporters & news gathering professionals. Note: To hear the mic signal while recording, you need to use a recording software app with a monitoring feature that amplifies and drives the signal to the headphones.