For a hard-working professional microphone designed to withstand the rigours of speech or music performances, try the HN-EDA91 from Honeywell. You can turn it on or off with the simple push of a butto
FMM-1 is a standard-sized module (typically mounts to a 4" [10.16 cm] square box) that supervises either a Class A (Style D) or Class B (Style B) circuit of dry-contact input devices.