C&E CNE01347 Headset Adapter 3.5mm Male to 2.5mm Female Connector - Non-Retail Packaging - Black 2. 5mm female to 3. 5mm male headset adapter Lets you use 2. 5mm headsets with mic for your phone Extends your headsets cable for further comfort This Headset Adapter simply plugs into any 3.5mm compatible device and can then transmit audio to any 2. 5mm headset.