Earmuff cable with x03s Connector.  ONLY for Ear Muff Headsets with Microphone.  CANNOT be used on Listen Only models.
Very similar to the Motorola 2-pin except this one has a screw to lock it in place.  Fits many HYT models including: TC-1600, TC-500, TC-600, TC-610, TC-620, TC-700, TC-700EX