A pop shield prevents pops from getting in your recording. Pops are developed when a microphone acquires fast bursts of air that are created as we speak plosives. Letters P, B, T or D are known as plosives mainly because they “explode” each time they are spoken. Pop shields function as a filter of these bursts of air to ensure that the mic doesn’t pick them up. A pop shield is clamped onto the microphone stand, not on the mic itself if not it might pick up noises as soon as the mic is shifted.