VAC is an adjustable pop filter for upgrading the quality of your vocals. The VAC system goes between the vocalist and the microphone, functioning as a variable acoustic compressor, filtering out popping and sibilance. It consists of two acoustic screens with a ball and socket precision positioning system that mounts on a gooseneck or at the end of a mic stand. You control the amount pop and sibilance filtering by using just one screen or adding the second screen and adjusting the distance between them. All standard 5/8" microphone threads.