YCS Basics Headphones + Mic/Stereo Headset Adapter Cable for Office/Home Phones See product description after the bullet points for important compatibility notes One 2.5mm TRS (Tip, Ring, Sleeve) 3 Conductor / 3 Pole male connector to one 3.5mm TRRS (Tip, Ring, Ring, Sleeve) 4 Conductor / 4 Pole female connector Adapter cable allows you to use a 3.5mm TRRS stereo headset or headphones with a built-in-microphone with home/office phones that use a 2.5mm TRS plug Compatible with gaming headsets that use a single 3.5mm TRRS connector. Compatible with Android / Apple headphones with built-in-microphone (compatible with devices that use the CTIA/AHJ wiring standard and is not compatible with the OMTP wiring standard)