The MUYHSMFFADW Headphone/Microphone Splitter features one 4-pole (4-pin) 3.5mm male (TRRS) and two 3-pole (3-pin) 3.5mm (TRS) female connectors, enabling you to add a mono microphone input, as well as a stereo output to your PC or Laptop, through a single 3.5mm audio port. While some of the newer laptops from Apple and Dell feature only a single (4-pole) 3.5mm audio port to support both audio input and output, this innovative headset splitter adapter breaks the audio port out into two distinct ports - one that can be used for a microphone input connection, and the other for connecting external (output) speakers. This headset splitter can be used with any portable device that uses a 4-pole 3.5mm mini jack, such as your iPhone, iPod and iPad, and features a compact, lightweight design that takes up very little space in your laptop bag. The MUYHSMFFADW 3.5mm headset splitter is backed by StarTech.com's lifetime warranty for guaranteed reliability.