I'm not sure if it's the fact that there were no instructions included in my packaging, or that the product works unreliably. By trial and error, I have managed to make this product useful most of the time. The on/off switch located on the boom mic must require a certain "touch" to trigger the voice prompts, because I have not been able to make it work all the time. That means, I can't reliably start a call or end one. But, when it works, it is great! You have to have set up a voice recognition phonebook, I think (but I can't be sure because I HAVE NO INSTRUCTION BOOKLET). The sound quality when you connect with your party is excellent, from both ends of the conversation.