The microphone does not transmit understandable sound to callers, but Speaker provides excellent sound. Family members cannot recognize my voice and say words are not clear. Even when I place microphone close to mouth, results do not improve. I am aware that the microphone is not the speaker, but is located near the phone plug end.After I disconnect the unit from the phone, (without disconnecting the call) my messages are easily understood using the phone microphone itself.In my Toyota Avalon, there is actually no room for mounting, so it just flopped on the console. Too bad that with today's technology Motorola couldn't miniaturize and condense the size of this unit and eliminate the heavy coiled cord, and have everything fit in the cigarette lighter socket. The cords were a nuisence, interferrng with transmission shifts. The Motorola unit might work on a Hum V or a Mack truck, I suppose.I tried to live with it, and searched for a remote microphone with the proper 3/32 male plug. I finally went to Radio Shack and found they could order one out for about $15.00, and it would take a few days. I finally opted to purchase a Radio Shack #1700917HFA for a Motorola V120 for $29.99. It features a remote mike and self contained unit that fits in the cigarette lighter with only one cord to the phone. I located the microphone above the driver's door, and the cord concealed under the rubber door seal, then under the dashboard, and it ends near the ash tray door. It plugs into the unit and works well. Sound quality is not as clear as the Motorola unit on my end, but those I phone hear clearly.If you purchased a Motorola Hands Free Unit, and the bulk is not a problem, and if you can find a microphone with a tight fitting male plug that will fit in the unit, you will probably be satisfied. Take the unit to the place where you go shopping for the microphone to be sure the plug fits tightly into the phone jack. The Motorola unit? It is sitting on my workbench as a reminder of my gullibility.