The Shure SM81 is a high-quality, unidirectional condenser microphone designed for studio recording, broadcasting, and sound reinforcement. Its wide frequency response, low noise characteristics, and low RF susceptibility have made it a standard for applications involving acoustic instruments, especially guitar, piano, and cymbals. 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. The SM81 is the perfect choice for a professional musician or sound engineer who is looking to mic up acoustic instruments such as acoustic guitar, piano and cymbals. It can ideally be used on stage and because of its high quality is also at home in the recording studio.  Features 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 Specifications Weight: 230 g Height x Width x Depth: 212.0 × 23.5 × 23.5 mm Frequency Response: 20 Hz – 20 kHz Frequency Response: Flat Sensitivity: -45.00 dBV/Pa – 5.60 mV/Pa Self-Noise: 16 dB(A) Max. Sound Pressure Level:800 ohm load: 136 dB (attenuator at 0) 146 dB (attenuator at -10), 150 ohm load: 128 dB (attenuator at 0) 138 dB (attenuator at -10) Transducer Type: Condenser Polar Pattern: Cardioid Switchable low cut: Yes Connectors: 3 Pin XLR Attenuator: Yes Interchangeable Capsule: No Main Functionality: Performance Headphone Output: No Requires Phantom Power: 11 to 52 VDC Cartridge: Fixed WATCH: Shure SM Microphones