The VAC-RE20 model is specifically designed to attach to the Electro Voice RE20 Microphone and its 309/A shock mount (one of the radio broadcast industry standard setups.)
Simply unscrew one of the thumbscrews on either side of the shock mount, install the VAC-RE20 and put the screw back. The VAC-RE20 tracks the microphone as it is moved. Each DJ can have their own set of screens and pop them in for their air time, especially helpful during flu season.