This is an audio adaptor suitable for using on Motorola GP344, GP328, GP344R, GP388, GP644, GP688 EX500, PRO7150 etc. The unit enables you to use an earpiece or headset which has a Motorola 2 pin plug fitted on the above radios. Remember, do not over tighten the securing screw otherwise you risk snapping it off in the radio body, finger tight is fine. Comes with integral dust cover to keep dirt out when not in use.