The WM625 and WM625S are designed especially for mounting to wall outlet boxes. The frequency response is shaped to provide crisp, clear, highly intelligible voice communications. Both models have a self-contained, rugged, low impedance dynamic cartridge assembly. The WM625S has a simple push-to-operate DPDT snap-action switch suitable for almost all switching requirements. For intercom and P.A. applications in security access, warehouses, factories, schools & fast food outlets. Frequency response tailored for crisp, clear speech intelligibility and communication. Push-To-Talk option (DPDT switch), Brushed stainless steel duplex plate, Mounting screws included.