The Motorola GP320 GP340 GP328 to threaded 3.5mm Visar audio adaptor
It can convert the Motorola GP320/GP340/GP360/GP380/GP328 to fit for the Motorola Visar threaded 3.5mm

Compatible with:

HT750, HT1250, HT1250LS, HT1550, HT1550XLS, MTX850, MTX850LS, MTX950, MTX960, MTX8250, MTX8250LS, MTX9250, PRO5150, PRO5350, PRO5450, PRO5550, PRO5750, PRO9150, PTX700, PTX760, PTX780 GP140, GP320, GP328, GP329, GP338, GP339, GP340,GP360, GP380, GP600, GP640, GP650, GP680, GP1280.