The Electro-Voice HM2 is a headset-sized condenser microphone suitable for public speakers and singers. It has a cardioid directional characteristic. Ideal for singing drummers or vicars, for example.
The Electro-Voice HM3 is a headset microphone specifically for public speakers and singers. It has an omnidirectional directional characteristic. This type of microphone is ideal for singing drummers, for example.
The RE97-2TX is a headset-sized condenser microphone with an omni-directional directional characteristic. You attach this set behind the left and right ear. Is practically invisible when worn.