The Anchor Audio CM-LINK Collar Microphone is made for wireless PA transmission and is designed to rest on your collar. In other words, it rests on the back of your neck and puts the mic in front of your face, and it lets you talk to your band or ensemble through a PA system!
The collar design is more stable than an over-the-ear-style microphone, and the included windscreen helps filter out breath and wind noise. The cardioid polar pattern means it is designed to only pick up what you say - not all the other noises around you.
The 3.5mm connector is designed to work with the Anchor Audio WB-LINK Wireless Bodypack Transmitter to get your audio where it needs to go without cables, but it will work with any transmitter with a 3.5mm connector.