I was surprised to see that there was no mute switch on this model. This can be very handy if your phone doesn't have one, letting you run water, answer a question, etc, without leaving the conversation entirely.I was disappointed to see that the batteries for the amplifier seem to be special (zinc air) that will go dead in two months regardless of usage. This makes the amplifier much less useful. The ear gel piece makes my phone seem louder so that I need the amplifier less. And the headset will work on the low setting even without any batteries. Overall volume and sound quality are good.But I'm going to try the plantronics m135 instead. It has a mute switch.