SHURE BETA 91A I am selling this because I don't use it often. The BETA 91A is a condenser boundary microphone with a half-cardioid polar pattern. It is optimized for low frequencies, so you can expect powerful low-end sound, studio-quality sound, and excellent attack and punch, even at very high sound pressure levels (SPL). - Uniform half-cardioid characteristics ensure a wide feedback margin and eliminate off-axis sound. - The integrated preamplifier and XLR connector, housed in a precision-machined, unobtrusive design, allow for neat wiring and quick, reliable setup. - Wide dynamic range for use in high SPL environments, and frequency response optimized for kick drums and bass. - A 2-position characteristic switch maximizes attack and clarity depending on the application. Selecting the flat characteristic provides a natural sound for many applications. The setting that boosts the mid-low range provides a punchy, powerful low end with sufficient high-frequency attack. - No external mounting hardware required. ■ Boundary Condenser Microphone ■ Half-cardioid polar pattern (picks up the hemispherical area above the microphone surface) ■ Frequency Response: 20Hz-20kHz ■ Output Impedance: 146Ω ■ Power: Phantom power 11-52V (48V recommended) ■ Output Connector: XLR3-pin (male) ■ Dimensions/Weight: 95W x 20H x 139Dmm / 470g