This covert acoustic RCA radio 2 pin earpiece can be used with the push-to-talk (PTT) button on the inline microphone, or as a voice activated unit (VOX). When activated on a Voice Activated Transmission (VOX) mode, the user can operate in total hands-free mode without having to use the PTT button. To disable the VOX feature, user simply set selector back to PTT.<br> <br> One wire leaves the radio and runs to a microphone push-to talk unit; the earpiece wire attaches at the microphone / push to talk unit. This earpiece must be clipped near the lapel, in law enforcement applications usually to the vest. The second wire runs under the shoulder to the back of the neck. It is best to run the wires under the uniform clothing to give suspects less to grab hold of. <br> <br> The audio quality for the this RCA 2 pin earpiece is exellent and works well in a variety of conditions. The microphone/ptt housing clips securely to your vest and lies flat so it is not easily displaced and can be pressed from the front without having to grab hold of the unit.<br> <br> <b>This earpiece for RCA radio features a 90 day "no questions asked" money back guarantee.</b>