100% new never used in factory box The SM500 is a single channel of BBE's renowned Sonic Maximizer in the API 500-Type chassis. SM500 500 Series Single-Channel Sonic Maximizer Specifications: A full-function, +4 Balanced BBE Sonic Maximizer Same Sonic Maximizer engine as the 882i Can be used with all types of music +23dB of output headroom 118dB signal to noise ratio 500-style Chassis Fits in Any 500 Rack 5 year warranty Frequency Response: 5Hz to 30kHz +/-0.5dBu, -10dBu input THD in process mode: less than 0.1% at -10dBu input, 20-20kHz Maximum Output: +23dB of output headroom Input Impedance: 47k Ohms Balanced Output Impedance: 600 Ohms Balanced Sensitivity: -45dBu for maximum process Maximum Process +12dBu boost at 5kHz Lo Contour: +12dBu boost at 50Hz All analog, through-hole circuit with only high-precision components used 1% metal film resistors throughout Authentic BBE proprietary, patented Sonic Maximizer Processor