Classic Unidyne® Instrument Microphone. Classic Unidyne instrument mic features selectable dual-impedance operation with a silent on/off switch.
The predecessor to the SM57, the 545SD Classic Unidyne® Instrument Microphone is a dual-impedance, unidirectional, dynamic microphone.
Shipped connected for low-impedance operation, the 545SD features a silent magnetic reed on/off switch with lock-on option. A favorite for instrument pickup and recording, the 545SD can also be used on lecterns in public address systems.