THE SM81 IS RUGGEDLY CONSTRUCTED. IT OPERATES ON PHANTOM POWER AND PERFORMS OVER A WIDE RANGE OF TEMPERATURES AND HUMIDITY CONDITIONS. IT IS FURNISHED WITH A SWIVEL ADAPTER, ATTENUATOR-SWITCH LOCK, FOAM WINDSCREEN, AND CASE FOR CARRYING AND STORAGE. OTHER ACCESSORIES ARE AVAILABLE. 20 HZ TO 20 KHZ FREQUENCY RESPONSE FLAT RESPONSE CURVE FOR ACCURATE REPRODUCTION OF SOUND SOURCES LOW NOISE AND HIGH OUTPUT CLIPPING LEVEL LOW DISTORTION OVER A WIDE RANGE OF LOAD IMPEDANCES CARDIOID POLAR PATTERN, UNIFORM WITH FREQUENCY AND SYMMETRIC ABOUT AXIS, PROVIDING MAXIMUM REJECTION AND MINIMUM COLORATION OF OFF-AXIS SOUNDS LOW RF SUSCEPTIBILITY SELECTABLE LOW-FREQUENCY RESPONSE: FLAT, 6 OR 18 DB/OCTAVE ROLLOFF 0 DB/10 DB LOCKABLE ATTENUATOR SWITCH PHANTOM POWERING (DIN 45 596 VOLTAGES OF 12 TO 48 VDC) RUGGED STEEL CONSTRUCTION FOR DURABILITY FIELD-USABLE OVER WIDE RANGE OF TEMPERATURE AND HUMIDITY CONDITIONS