SP4-SL - Zapco Reference Series Pre-Amp EQ Max Output Level/Balanced: 16 volts EQ Center Frequencies: 40HZ, 125 KHz; 1KHz, 12KHz Max Boost Cut: +/- 18dB Dimensions: 5.25"D x 6.25"W x 0.95"H Includes (3) 18Ft DIN-to-RCA Cables