Motorola Original PMMN4021 PMMN4021A Speaker Microphone Compatible with HT750, HT1250, HT1550, MTX850, MTX1850, MTX8250, MTX950, MTX9250, PR860, PRO 5150 Compatible with HT750, HT1250, HT1550, MTX850, MTX1850, MTX8250, MTX950, MTX9250, PR860, PRO 5150 "Windporting Technology" 3.5mm unthreaded jack on the head of the microphone