While many lav microphones are omnidirectional, meaning they capture an equally strong signal from all directions, there are quite a few lav mics that are made with a cardioid or hypercardioid pattern. This becomes important when clipping a microphone, so that you know which style you own, because you’ll need to point the end of the microphone in the direction of your talents mouth if you have anything but an omnidirectional mic. Too often I see camera operators clipping a mic onto someone that is pointed away from their mouth, and the cam op doesn’t know the pickup pattern of the lav they are using.