The model 503BG is a Unidirectional Dynamic Microphone developed for computer voice recognition applications. The microphone offers excellent voice fidelity while reducing background noise. Also use the 503BG in other close-talking applications such as paging and talkback. The 503BG features a low-impedance, moving coil type transducer with an integral humbucking coil and an attached two-conductor shielded cable with a built-in strain relief. It produces a frequency response with an essentially constant output voltage over the voice spectrum when used close to the sound source. The 503BG’s case is aluminum with a black enamel finish. It mounts to a gooseneck, a fixed pipe or a microphone stand using a standard 5/8”-27 thread. To secure the mounted BG503, tighten the 4-40 screw with the supplied #4 Allen (hexhead) wrench.